Verse 6: And before the throne there was (Ex. 38:8; Rev. 15:2) a sea of glass like unto crystal: (Ezek. 1:5) and in the midst of the throne, and round about the throne, were four beasts full of eyes before (Rev. 4:8) and behind.
[And, etc., καὶ—ὡς θάλασσα ὑαλίνη, etc.] There was also before the throne a sea of glass like unto Crystal (Beza, Piscator, similarly the Vulgate, Montanus, Erasmus, etc.). In the Tabernacle and Temple there had been a Sea, that is, an enormous basin full of water, Exodus 30:18; 1 Kings 7:23; 2 Chronicles 4:2 (Grotius, similarly Durham). In this the Priests were washing both themselves and the sacrificial victims, when they were approaching unto the altar: which was both for ornament and use, and was aptly shadowing forth Christ, through whom we and our sacrifices are made agreeable, when we approach unto God (Durham). Mention is made of this sea also in Revelation 15:2 (Cluverus). This sea denotes, either, 1. Baptism (most interpreters in Zegers), which is compared to the Red Sea, through which he that desires to approach unto the throne of God ought to pass (certain interpreters in Gomar); which is compared to glass and to crystal on account of its purity and efficacy in cleansing (Zegers). Or, 2. the pure word of God, which is before the throne; for it is conjoined with the Spirit, and in this we look upon the glory of God, Isaiah 59:21; 2 Corinthians 3:18; which is compared to water, on account of its cleansing and reviving power; to glass, on account of its placid tranquility; and to crystal, on account of transparency (Forbes). Or, 3. the blood of Christ, which actually does what the Sea in the Temple did in type. To this agree, both the scope, which is to reveal the glory of God in the Church; for this blood is among its principal ornaments, Hebrews 12:23, etc.: and that this justifying blood is aptly conjoined with the sanctifying Spirit here already previously mentioned. It is called a sea on account of its plenitude and its great power; and it is said to be before the throne, so that we might be taught that God procured this blood, by which those cleansed are able to approach unto God with confidence, Hebrews 10:19; and to be of glass like unto crystal, to express its excellence and its aptitude to contain and preserve that which is in it clean and pure; and at the same time so that we might be admonished how reverently and cautiously this blood is to be handled, lest it be trampled upon, etc. (Durham). Or, 4. the multitude of blessed souls abiding in heaven. The sea denotes the multitude of them; the glass, their tranquility of life; the crystal, the solidity and firmness of the glory and felicity that they have (Pererius). Or, 5. the surpassingly great multitude of Angels, of which the splendor, and tranquility and purity of life, are aptly signified by glass and crystal (Andreas Cæsarius and Arethas in Ribera, similarly Gagnæus). But this is refuted by a comparison with Revelation 15:2 (Ribera). Or, 6. the world (Piscator, Pareus out of Bullinger), that is, mankind, restless by nature (Piscator); or the multitude of men living on the earth (Ribera, Pareus): For waters are the peoples in Revelation 17:15. Sea signifies multitude in Habbakuk 2:14 (Grotius, similarly Ribera, Pareus). He calls this sea glassy, just as also the Poets (Ribera); as in Horace’s Odes 4:2, he is going to give names to the glassy sea (Ribera, thus Grotius), and in Odes 3:13, O fountain of Blandusia, more splendid than glass (Ribera): and that either, 1. on account of the fragility of the world (Pareus out of Bullinger); or, 2. because God sees through the actions and deliberations of the people (Grotius, similarly Ribera, Gomar), so that He might rightly judge and render to each one according to his works. He adds like unto crystal for the sake of amplification, that is to say, clear and altogether transparent, for crystal is more transparent than glass (Ribera). The sea of Solomon was of brass, but ours is more transparent. Perhaps there is an allusion to the basin of the Mosaic Tabernacle, which was cast, I do not know how, from the material of the lookingglasses, Exodus 38:8 (Mede’s Works 543), which nevertheless I do not deny to be brass, since the Text clearly says it (Mede’s Works 508). Or, 7. the common people of Jerusalem, that is, who had enlisted to Christ; which recalls Crystal by its great purity, which is described in Acts 2 and 4. There is a particular brightness to crystal. See Ezekiel 1:22 (Grotius). Or, 8. the empyreal heaven (Pererius, Lapide, Menochius, thus Cotterius), the greatness of which signifies the sea, the tranquility indeed and the strength and the clarity, glass like unto crystal (Pererius, thus Lapide). Or, 9. the ground and, as it were, the pavement of the heaven of the blessed, through which, as through a sea of glass and crystal, God observes all things which are on earth, etc. (Gomar).
And before the throne; the throne mentioned before, Revelation 4:2, 3, upon which one sat, etc. A sea of glass like unto crystal; another allusion to the tabernacle or temple, in which was a sea, that is, a large vessel full of water; it was for Aaron and his sons to wash their hands, and feet, and sacrifices in, Exodus 30:19; 1 Kings 7:23; it was ten cubits broad, five cubits high, and thirty cubits about. Here it is said to have been of glass; this, probably, signified the blood of Christ, in which all those souls and services must be washed which are accepted of and acceptable unto God. Its being represented here as of glass, may signify the purity and spotlessness of him whose blood it was. Other guesses there are many at the significancy of this sea of glass, but this seems to me most probable, because the use of the sea in the temple is made good in Christ.
[And, etc., καὶ ἐν μέσῳ τοῦ θρόνου, καὶ κύκλῳ τοῦ θρόνου, etc.] Now, in the midst (or, view [Vulgate]) of the throne, and in the circuit of the throne (or, and within the throne, and what things were encircling the throne [Beza]) were four living Creatures full of eyes before and behind (Piscator, similarly Montanus, Erasmus). There is an allusion here, either, 1. to the four camps of Israelites around the Tabernacle, to the four beast-banners of the living Creatures (Mede’s Works 544). To which it is objected that the four living Creatures are here nearest to the Throne, and are closer to it than the twenty-four Elders, while those camps in Numbers 2 were more remote than the Levites (Hammond). Or, 2. to those four living Creatures in Ezekiel 1 (Ribera, similarly Pareus, Napier), yet with these differences, that there they had four wings, here six, for greater swiftness; there every one had four facies, here the faces were separated; there were signs, etc. (Napier). In the Tabernacle, in the Temple of Solomon, and in the Vision of Ezekiel, there were two similar figures, composed of the forms of a group of four living Creatures; but here, as the following things teach us, the four forms of the living Creatures were distinct. Why? Because all things are formed more distinctly in the New Testament than in the Old Testament (Grotius). Now, here the four living Creatures designate, either, 1. the Four Gospels with the Evangelists (Cluverus, Napier, Ribera), which is the most widely received opinion of the ancient and more recent men, like Irenæus, Athanasius, Augustine, etc. (Ribera). For these agree with the living Creatures, both with respect to the office of praising God and of adorning the throne, and in number, and in titles, as we shall see (Napier’s Plaine Discovery of the Whole Revelation of St. John 25). This does not satisfy; 1. for John, whom they maintain to be the fourth living Creature, was yet dwelling in the earth; but he introduces those four living Creatures as abiding in heaven, and blessed, and speaking with him, and teaching him, Revelation 6 (Pererius). 2. It is manifest that they were led unto this opinion by an argument taken from the twenty-four Elders, which are books, whence also the vision admits the four living Creatures as books. But it is objected that the Apostolic Epistles, as must as the four writings of the Evangelists, make up the Scriptures of the New Testament. I prefer, therefore, that the four living Creatures are the fourfold truth of the Gospel (Cotterius). 3. Because the attributes of the Animals do not agree with the Evangelists, that they fell prostrate before the lamb, Revelation 5:8; taught John, Revelation 6:1, 3, 5, 7; gave vials to the Angels, etc., Revelation 15:7 (Gomar). [These things concerning the first opinion.] Or, 2. four Apostles (Grotius, Hammond), or Apostolic men, who were at that time at Jerusalem, the beast-banners, as it were, of the camps of Christ (Grotius); who certainly were both superior to the Bishops of Judea, and in a certain sense inferior to James, who was the Bishop there, that is, the supreme governor, in that Jerusalem Council, Acts 15, to which this representation has regard (Hammond). Or, 3. the ministers of the Gospel Church (Durham, Forbes), as many things suggest, 1. the name of living Creatures: for they have natural life in themselves and beget spiritual life in others, 1 Corinthians 4:15; Galatians 4:19. 2. The place of them, in the midst of the throne and elders (Forbes); who are the faithful, from whom they are distinguished, and before whom, as leaders, they go in the worship of God, those also stirring unto their duties, Revelation 6:3, 5, 7 (Durham), and ministering to them grace from God (Forbes). 3. For they are described as Cherubs or Angels in Ezekiel 1, but such as are members of the Church militant (Durham). 4. Because they are four (Forbes, Durham), that is, fewer than the Elders or the Faithful (Durham), but sufficient, who advance into all quarters (Forbes, Durham), like those four ministers of providence, Ezekiel 1, and the four chariots, Zechariah 6, and the four Angels, Revelation 7:1 (Forbes); and they look out for the Church on every side of the Throne (Durham). 5. Because to these all the properties of the living Creatures agree (Forbes, Durham) [as we shall see]. Or, 4. four blessed spirits abiding in heaven (Pererius). To which it is objected, 1. that they are in the earth, Revelation 5:10, and on mount Zion, Revelation 14:1, 3, which is a type of this, rather than of the future, Church: 2. that they are manifestly distinguished from the choir of the heavenly blessed, Revelation 7:11: 3. that the souls of the saints would ineptly be called Animals, Lions, Oxen, etc. (Cluverus). Or, 5. Angels (Pererius, Gomar, Piscator, Bochart’s A Sacred Catalogue of Animals 1:3:6:769, Menochius), even indeed the more excellent (Gomar, similarly Menochius); or, Archangels, since they were placed in command of other Angels, and to the latter the former assign their tasks, as in Revelation 15:6, 7 (Bochart’s A Sacred Catalogue of Animals 1:3:6:769), who minister to God in the four quarters of the world (Piscator), and were put in charge of the Church, as much as of the circle of the earth. It favors this opinion, 1. that they are often called Cherubs in Ezekiel 10: 2. that by these the mysteries of the visions were explained to John, as by the Angels to Ezekiel, to Daniel, and to Zechariah (Bochart’s A Sacred Catalogue of Animals 1:3:6:769): 3. that to these agree the following descriptions (Gomar, Bochart’s A Sacred Catalogue of Animals) [as we shall see]. But it hinders, 1. that these are manifestly differentiated from the Angels, Revelation 7:11 (Pareus): 2. that these sing with the elders, Revelation 5:9, thou has redeemed us…and hast made us kings and priests (Pareus, similarly Cluverus). Or, 6. the Christian Churches in the four quarters of the world, which correspond to the four Israelitish camps (Mede’s Works 544); or the universal body of the Church or of the faithful (Dieu in Mede’s Works 704): or, the Apostolic Church triumphant in the heavens; just as the twenty-four elders denote the Church of the Patriarchs and Prophets before Christ. Therefore, the Elders are standard-bearers of the old, the living Creatures of the new, Church triumphant (Pareus). But since these are diffentiated from that innumerable multitude, gathered from every nation, of the elect triumphant in heaven, Revelation 7:11, and from the one hundred and forty-four thousand triumphant over the Beast, Revelation 14:3, hence it is clear that not just any Elect indifferently and promiscuously, but certain excellent and more eminent ones, nobles, as it were, of the whole Church, are denoted (Cluverus). [And let these things be said concerning the first question; two things yet remain to be asked.] Questions 1: What does this mean, that he says that these living creatures are full of eyes before and behind? Responses: 1. [It is taken] from Ezekiel, where by the word עֵינַיִם, that is, ὀφθαλμοὺς/eyes, we said that colors were signified. Now, those colors here signify the multiform gifts of God, by which the Apostles knew both present and future things, Matthew 13:52 (Grotius). 2. This means that the wisdom of the Gospel shined with great fullness upon the faithful servants of God both before, that is, that it shined out before the birth of Christ, and behind, that is, thereafter unto the end (Cotterius). 3. This means that, whether they press unto things before them, or go backwards, they never stumble or stray. The Evangelists, whether they speak of future things, like the destruction of Jerusalem, etc., or of past things, everywhere they write true things, both useful and full of Divine light (Ribera). 4. Such a great number of eyes denotes a multitude of men profoundly insightful, and superabounding in the knowledge of the mysteries of God, which sort of men are in the Churches (Mede’s Works 544). 5. This denotes the knowledge and vigilance of the Ministers, who are, as it were, sentinels in watchtowers, and they are obliged to take heed unto the throne, and themselves, and the Church; Acts 20:28; 1 Timothy 4:16 (Forbes). They have eyes both before, that is, towards God, upon whom they depend, so that they might be directed by Him, as in Psalm 123:2; and behind, that is, towards their people, so that they might point out to them the way (Durham). 6. It signifies a most complete power of understanding, even of things most obscure and hidden, which is in the Angels (Pererius); their double vigilance is denoted partly inwardly, in observing the will of God, partly externally, in observing the creatures, to which they are sent, either for salvation, or for punishment. Question 2: How, without contradiction, are these living creatures said to be both in the midst of the throne, and in its circuit (καὶ ἐν μέσῳ τοῦ θρόνου, καὶ κύκλῳ τοῦ θρόνου) (Gomar)? Response 1: It is ἓν διὰ δυοῖν, an hendiadys, as if he had said, ἐν μέσῳ τοῦ κύκλου (that is, περιβόλου) τοῦ θρόνου, in the midst of the very circuit, or orbit, of the Throne: if, by which Throne, as a square, he indicates a quadrangular, parallel figure, you should make a circle from the Throne and the Presbyters surrounding it at a distance, in the midst or towards the middle of each one of the sides of the quadrangle (for ἐν μέσῳ, in the midst, is to be taken distributively) the four living Creatures were presenting themselves; namely, one in the midst of whichever side (Mede’s Works 544). Ἐν μέσῳ is to be taken for ἐν διαμέτρῳ, in the diameter, so that it might indicate that they were positioned diametrically around the throne (Mede’s Works 1122). But this exposition is harsh; it would be smoother if it were read ἐν μέσῳ καὶ κύκλῳ τοῦ θρόνου, in the midst and circuit of the throne. But the word θρόνου/throne is here expressed twice, by which it is indicated that the middle is to be distinguished from its circuit. And it is more harsh to set four middle things in the place of a number of quadrangles (Dieu in Mede’s Works 704). I acknowledge, and give thanks to thee, that thou hast freed me from that exposition (Mede’s Works 707). Response 2: These words are to be understood κατὰ πόδα, in quick succession, namely, that he saw the four living Creatures in two places; 1. in the circuit of the Throne, in which the Reverend man rightly teaches that there is an allusion to the four living Creatures imprinted on the banners of Israel, etc.; 2. in the midst of the Throne, which I refer to Ezekiel 1:10, where those four living Creatures appeared within, not without, the Temple, as it is evident out of Ezekiel 10:3-5, 14. Whatever it might be, it conveys great comfort to me that the four living Creatures, which denote the Church, were observed, not only around the throne, but also in the very midst of it. For, even if by reason of the external ministry they were directed by the twenty-four elders toward the body of the faithful only in the circuit of the Throne, indeed in the circuit of those very elders; yet by reason of their communion with Christ, who Himself sits upon the throne, they themselves are also rightly arranged within the throne, and by the four faces of the Cherubs standing within the Tabernacle before God they are represented (Dieu in Mede’s Works 704). With these things gathered, I perceived that my mind was overspread by an unexpected light, and immediately passed over to that opinion that the Seat on which God was sitting was without doubt carried by the four living Creatures, of which the several living Creatures in the circuit of the throne, with their hinder parts hidden within, turned their faces unto ὁμοειδῆ, those corresponding, to them; as we read in Ezekiel that God was conveyed upon Cherubs visible with the fourfold face of the same living Creatures (Mede’s Works 707). There is here, therefore, no contradiction, for these things are not said according to the same thing, or according to the same part of the Animals. For with respect to the posterior part of the body they were under the midst of the Throne: but with respect to the head and anterior part they were before the Throne, in a suitable order in the circuit of the throne. As similar ornaments are wont to be added to Royal seats; so on the steps of the Throne of Solomon twelve lions were spread out (Gomar), even as twelve oxen bore the sea of brass, 1 King 7:25 (certain interpreters in Pareus). And in this position, the subjection and servitude of the Angels towards God is depicted (Gomar). But this opinion is not able to stand firm. For thus the living creatures would have stood immobile. But they are frequently read to have fallen prostrate and to have worshipped: also one of them distributed the vials, Revelation 15:7 (Pareus). Response 3: It does not mean that all the living Creatures were both in the midst and in the circuit (Ribera); but three were in the circuit of the Throne, but the Eagle was above in the midst of the Throne (certain interpreters in Gomar, thus Ribera), that is, within the extent of the seat, before the face or breast of the One sitting, as it were (Ribera); for it is not only said that the fourth living Creatur was like unto an Eagle, but like unto an Eagle flying (certain interpreters in Gomar). Response 4: The living Creatures were not in the circuit and midst of the Throne at the same time, but by intervals of time, now circling the Throne, and at other times proceeding within the middle circuit of the Throne (Pererius). Response 5: Concerning the four living Creatures, one was on the steps which were before the throne (see 1 Kings 10:19); two were on the sides; one was behind, and thus they were nearer to the throne than the Presbyters. The steps are taken as part of the throne (Grotius). Others: Two stood in the midst, that is, over against the midst of the Throne, and that before it; the other two ἐν κύκλῳ, in the circuit, which in Revelation 4:4 was κυκλόθεν, that is, on either side, one on the right hand, the other on the left (Piscator). Others: ἐν μέσῳ, in the midst, is able to signify the anterior part, as to be ἐν μέσῳ in Acts 1:15; 4:7: it is the same as to be in an especially conspicuous place, where all were able best to see and hear. Wherefore κύκλῳ, round about, which is set opposite to it, will be the same as ὄπισθεν/behind, and will denote the posterior part (Hammond). Others: That ἐν μέσῳ, in the midst, does not denote the center of the seat in a mathematical sense, but proximity in a proverbial sense, and means near, or among, as in Job 1:6; Matthew 10:16. See Revelation 5:6. They were, therefore, near the Throne, even nearer than the elders, as if given preference in dignity before them. What is added, and in the circuit of the throne, specifies the situation, that they stood near the Throne in such a way that they were most nearly surrounding the four sides of the Throne, and were, as it were, touching it (Pareus). They are said to be both in the midst of the throne, that is, near that as if on the same Throne with God; for Ministers act in the place and name of the Lord, 2 Corinthians 5:20; and in the circuit of the throne, which is not to be understood as if they were beyond the extent of the Throne, but it denotes the wisdom of God; for He arranges them, not together, but on every side, so that they might be able to be serviceable for the edification of the Elders, or of the people, which the former, who were standing around the Throne, shadow forth, as previously mentioned (Durham). Response 6: The article τῷ/the before κύκλῳ/circuit is omitted in accordance with a Hebraism. Therefore, thus I render the words, Both within the throne and those which are around the throne (Cotterius).
John in this vision also saw four beasts, which beasts are said, 1. To be in the midst of, and round about the throne. 2. To be full of eyes before and behind. 3. They are, verse 7, said to have resembled a lion, a calf, a man in the face, and a flying eagle; verse 8, each of them had six wings, and they were full of eyes within, and incessantly glorified God. Question: Whom did these beasts signify? Solution: There are various notions about them. Some judge them the four evangelists; but John himself was one of these, and yet alive. Some will have them four apostles that were mostly at Jerusalem; but I see no ground for that. Some will have them angels; others, glorified saints; but we shall afterwards find them distinguished from both these. Others will have them the whole church. But the most probable sense is, that they represented the ministers of the church, who are living creatures, whose place is betwixt God and his church, as those beasts are placed betwixt the throne and the elders; and who are but four to the twenty-four elders, being but few in comparison with the multitude of believers; and yet have eyes on all sides, being enough to see to the affairs of the whole church of Christ on the earth. In this sense I rest; only here remains a question, how these are said to be in the midst of the throne, and yet round about the throne? To which various answers are given; that which pleaseth me best is, ἐνμέσῳ, in the middle, is not to be strained to signify a place at equal distance from two extremes, but more largely and proverbially for near the throne, or near him who sat upon the throne. See the several notions about this phrase in Mr. Pool’s Latin Synopsis.
 Greek: καὶ ἐνώπιον τοῦ θρόνου ὡς θάλασσα ὑαλίνη, ὁμοία κρυστάλλῳ. καὶ ἐν μέσῳ τοῦ θρόνου καὶ κύκλῳ τοῦ θρόνου τέσσαρα ζῶα γέμοντα ὀφθαλμῶν ἔμπροσθεν καὶ ὄπισθεν.  1 Corinthians 10:1, 2.  Hebrews 10:29.  Henrich Bullinger (1504-1575) was a Swiss divine, the successor of Zwingli in Zurich. He endeavored to unite the Lutherans and Calvinists. He wrote In Apocalypsim Conciones Centum, as well as the Second Helvetic Confession, the Decades, and, with Calvin, the Consensus Tigurinus.  The fountain of Blandusia is thought to have been in Horace’s home villa.  1 Kings 10:20.  Revelation 4:4a: “And round about (κυκλόθεν) the throne were four and twenty seats…”