Verse 8: And the four beasts had each of them (Is. 6:2) six wings about him; and they were full of eyes (Rev. 4:6) within: and they rest not (Greek: they have no rest) day and night, saying, (Is. 6:3) Holy, holy, holy, (Rev. 1:8) Lord God Almighty, (Rev. 1:4) which was, and is, and is to come.
[And, etc., καὶ—ἓν καθ᾽ ἑαυτὸ εἶχον ἀνὰ πτέρυγας, etc.] And the four living creatures each (or, each by itself [Pagnine, Beza, Piscator]) had (or, one according to itself, the individuals had [Montanus]) six wings in circuit (Erasmus, Illyricus, Tirinus, etc.), that is, on each side, as κύκλῳ, round about, is taken in verse 6 (Piscator). All suitable for flying (not like those in Isaiah 6), so that, whichever way they would fly, they might be abundantly equipped with wings, for swiftly bringing help to those fallen in weakness, etc. (Forbes). By the senary number of wings (which number is complete) he understands the perfect power and ability of flight, and the marvelous agility found in the Angels, etc. (Pererius). Others: These wings signify that most rapid progress of Evangelical preaching (Cotterius, similarly Zegers, Cluverus). Wings denote agility and alacrity in executing the command of God; wings having eyes, zeal conjoined with knowledge and faith; six wings in circuit, ready to fly in whatever direction, that is, most ready to fulfill the commandments of God universally and wholly (Mede’s Works 3:544). Others: The Evangelist have six wings in circuit, for, from whatever direction they are considered, they are not slow, but they fly, and are raised in all things unto the sublime. Thus I would explain it, if all the wings were devoted to flight, which I do not think (Ribera). Others: This is taken from Isaiah 6:2, where there are so many wings (Pareus, similarly Ribera, Lapide, Menochius, Cluverus, Durham, Grotius): with two of which they were covering their face, with two their feet, and with two they were flying (Menochius, similarly Piscator, Pareus), that is, they had them extended, as if prepared and ready for flight (Menochius, Ribera). The face of Christ is His Divinity; the feet are His Humanity, which the Seraphim as yet cover; they show that in this age those things are largely unknown to men. Here, therefore, it is indicated that many and great mysteries lie hidden in the Gospels, etc. (Ribera). Bishops are compared to Angels; but the Apostles to Seraphim, the greatest of the Angels: The Apostles cover their face before God through ταπεινοφροσύνην/humility in the soul, and through δουλαγωγίαν/ subjection of the body, in which are Fastings. Feet, that is, those things of which one ought to be ashamed, that is, sins, they cover through a contrite Heart and emended Life. Now, they fly by Faith and Love. Behold six wings, very excellent ones. With these flappings one goes to the Throne of God (Grotius). Two wings cover the face, so that they might denote the reverence of God found in Ministers, as in Malachi 2:5. Two cover the feet, so that they might denote their fear and humble sense of their infirmity, as in 1 Corinthians 2:3. Two are serviceable for duty, for flying, and they denote prompt and ready obedience to God, etc. (Durham).
And the four beasts had each of them six wings about him: the seraphims in Isaiah’s vision, Isaiah 6:2, had so; there their use is declared,—with twain he covered his face, with twain his feet, and with twain he did fly. If we understand all the wings here for flight, they signify the readiness of God’s ministers to move every way that God will send them: if we understand them as interpreted by Isaiah 6:2, they signify their various graces, their fear, dread, and reverence of God; their humility and modesty; their agility, or readiness to obey all the commands of God.
[And, etc., καὶ ἔσωθεν γέμοντα ὀφθαλμῶν] And within (that is, inside the wings [Menochius], or, under the wings [Piscator, Ribera]) they were full of eyes (Beza, Piscator, etc.). See what things were said on verse 6 (Menochius). But there the eyes were before, which regards their dependence on God, and behind, which denote their care of the flock; here within, which signifies that Ministers look also to themselves and to their own progress, according to Acts 20:28; 1 Timothy 4:16; otherwise they would be blind leaders, Matthew 15:14 (Durham). Others: The Evangelists have eyes within, for in mysteries, which are covered in the letter, and mystical senses, they are also full of Divine light, and they know whither they tend, etc. (Ribera). Others: It signifies that the whole Angelic nature, not in one part only [like men], but after its own kind is perfectly intelligent (Pererius). That κυκλόθεν, round about [which preceded], pertains entirely to this, not to the preceding. For the six wings which cover the face and privy parts, and with which he flies, are not able to be in circuit. But κυκλόθεν and ἔσωθεν mean without and within. Those multiform gifts given to the Apostles both were in the soul, and were appearing externally. Thus 1 Kings 7:36, ἔσωθεν, κυκλόθεν, within, round about, that is, ἔσωθεν καὶ κυκλόθεν, within and round about, or ἔξωθεν/without (Grotius). Κυκλόθεν καὶ ἔσωθεν, round about and within, is the same as ἔμπροσθεν καὶ ὄπισθεν, before and behind, in verse 6. Thus these things are able to be reconciled, if you consider the two parts of the surface as convex, that is, the circumference, and concave, that is, the interior; which two are able aptly to be expressed in both ways, the exterior or circumference by κυκλόθεν, round about, the concave by ἔσωθεν/within: and again on the living Creatures (concerning which these things are said, of which the posterior parts are properly convex, and the anterior parts, especially since they have wings, which effect a certain semicircle, are concave surfaces), the encircling surface is expressed by ὄπισθεν/behind and the internal surface by ἔμπροσθεν/before. As, therefore, ἔμπροσθεν/before in verse 6 is the same as ἔσωθεν/within, so κυκλόθεν, round about, and ὄπισθεν/behind are the same, which is also proven out of Revelation 5:1, where ἔσωθεν/within is put with ὄπισθεν/behind. Moreover, the eyes before are here able to denote the prescient or prophetic spirit of the Apostles; the eyes behind are able to regard the prophecies and types of the Old Testament, which they were best able to explain unto the conviction of the Jews (Hammond).
And they were full of eyes within: this denotes that large measure of knowledge, and diligence, and watchfulness, which should be in a minister of Christ.
[And rest (that is, cessation, as rest is often taken [Gagnæus]) they have not, etc.] That is, they extolled God in the heavens without end or intermission (Pareus). With diligent and sober zeal in this they act, etc. (Durham, similarly Cluverus). This is explained in Acts 20:31 (Grotius, thus Durham, Cluverus), and 2 Timothy 4:2; Isaiah 60:11 (Cluverus). As far as nature was allowing, they were not suffering any time to be free from labors for the praise of God. It is taken from Isaiah 62:6 (Grotius).
[Holy, holy, holy] It is taken from Isaiah 6:3, that is, Infinitely holy. This shows both how great faithful Ministers esteem the holiness of God, and that it is their duty to extol this perfection of God (Durham). It is a custom of the Hebrews to repeat a word three times in matters that they wish vehemently to impress, Jeremiah 22:29; Ezekiel 21:27 (Grotius). Others: He repeats it three times, so that he might signify the Holy Trinity in the unity of essence (Menochius, similarly Piscator, Cluverus). The ἅγιος/holy is repeated nine times in all my Codices (Valla): thus in the Spanish exemplar (Erasmus). But it is read only three times in most manuscripts (Grotius), and in my codices (Erasmus).
[Lord God Almighty] See on Revelation 1:8 (Grotius).
And they rest not day and night, saying, Holy, holy, holy, Lord God Almighty: this was the song of the seraphims, Isaiah 6:3, and shows how much it should be the care of ministers to make God known in all his attributes, his holiness especially, and his power.
[Who was, and who is, etc.] This is the proper name of God (Beza). See on Revelation 1:4 (Beza, Menochius, Grotius). [The sense:] Who promises, and who fulfills His promises, and will fulfill (Grotius). Here is the sum of the doctrine of the Gospel (certain interpreters). The Gospel teaches that God is, 1. Holy, that He takes away sin, and sanctifies His people; 2. our Lord, for He redeemed us, etc.; 3. Omnipotent, for He did great things for us. This teaches that God was, for the promise of a blessed seed was made from the beginning of the world; and is, for He defends His Church and perfects it more and more; and is to come, namely, unto Judgment (Cotterius). The holiness of God is all the more admirable inasmuch as it is joined with absolute power; His Truth confirms the certitude of His promises, is constant and reliable, as He is eternal and immutable, who is the same yesterday, and today, and forever. Behold the entirety of Religion. He, therefore, is to be feared, to be served, and faith is to be place in Him alone (Forbes).
Which was, and is, and is to come; and his eternity and simplicity, as he is the same yesterday, today, and for ever, without variableness or shadow of change.
 Greek: καὶ τέσσαρα ζῶα, ἓν καθ᾽ ἑαυτὸ εἶχον ἀνὰ πτέρυγας ἓξ κυκλόθεν, καὶ ἔσωθεν γέμοντα ὀφθαλμῶν, καὶ ἀνάπαυσιν οὐκ ἔχουσιν ἡμέρας καὶ νυκτός, λέγοντα, Ἅγιος, ἅγιος, ἅγιος Κύριος ὁ Θεὸς ὁ παντοκράτωρ, ὁ ἦν καὶ ὁ ὢν καὶ ὁ ἐρχόμενος.  Greek: ἀνάπαυσιν οὐκ ἔχουσιν.  Revelation 4:8a: “And the four beasts had each of them six wings about (κυκλόθεν) him…” Revelation 4:6b: “…and in the midst of the throne, and round about (κύκλῳ) the throne, were four beasts full of eyes before and behind.”  See, for example, Colossians 3:12: “Put on therefore, as the elect of God, holy and beloved, bowels of mercies, kindness, humbleness of mind (ταπεινοφροσύνην), meekness, longsuffering…”  See 1 Corinthians 9:27: “But I keep under my body, and bring it into subjection (καὶ δουλαγωγῶ): lest that by any means, when I have preached to others, I myself should be a castaway.”  Revelation 4:8a: “And the four beasts had each of them six wings about (κυκλόθεν) him; and they were full of eyes within…”  1 Kings 7:36: “For on the plates of the ledges thereof, and on the borders thereof, he graved cherubims, lions, and palm trees, according to the proportion of every one, and additions round about (וְלֹי֖וֹת סָבִֽיב׃; ἔσω καὶ τὰ κυκλόθεν, within and round about, in the Septuagint).”  Revelation 5:1: “And I saw in the right hand of him that sat on the throne a book written within and on the backside (ἔσωθεν καὶ ὄπισθεν; most Byzanting manuscripts read ἔσωθεν καὶ ἔξωθεν), sealed with seven seals.”  A good number of Byzantine manuscripts have this reading.  The Complutensian Codex.