Verse 1: And (Rev. 5:5-7) I saw when the Lamb opened one of the seals, and I heard, as it were the noise of thunder, (Rev. 4:7) one of the four beasts saying, Come and see.
[And (or, afterwards [Beza, Piscator]) I saw] With the song now finished (Grotius).
[That, etc., ὅτι—μίαν, etc.] When (or, after [Cotterius]) the lamb (that is, Christ) had opened (Camerarius, Ribera, Gagnæus) the first (μίαν/one, that is, πρώτην/first [Beza, thus Camerarius, Piscator, Grotius]; as it appears from the following [Grotius, thus Piscator]: Thus one is in the place of first, Genesis 1:5 [Pareus] and Matthew 28:1 [Piscator, thus Grotius]) of the seals. The opening here signifies the revelation of the counsels of God concerning the future lot of the Church made to John (Pareus).
And I saw, etc.: John’s vision continueth still: by the Lamb he means Christ, the Lamb oft mentioned Revelation 5; and by one of the seals, one of the seven seals mentioned Revelation 5:1, that were set upon the book which John saw in the right hand of God the Father, given to Christ, Revelation 5:7. Christ began to discover the counsels of God relating to that first period of his church.
[I heard one (that is, the first [Drusius, Piscator, thus Grotius], because the second, etc., follows [Grotius]) of the four living creatures] Having the form of a lion, Revelation 4:7 (Pareus, similarly Menochius, Piscator, Ribera out of Arethas), so that he might denote the undaunted courage of those preaching in the first beginnings of the New Testament (Cluverus, thus Durham), standing in the East (Mede’s Works 547), for thence the Actors, Christ and His Apostles, came (Mede’s Works 1123). The prince of the Apostolic assembly, Peter, who was also the first in the preaching of the Gospel, of which preaching it is here treated, appears to address John here (Grotius).
[As the sound of thunder] That is, a voice great and resounding (Grotius, similarly Menochius, Cluverus), terrible (Ribera, Menochius), and most powerful (Cluverus): by which he denotes the power of the Evangelical word, etc. (Durham). He was a Lion, of which the roar is after the likeness of thunder (Pareus). John and his brother were called sons of thunder, Mark 3:17 (Grotius).
[Come and see] A phrase everywhere met with in the Rabbis (Louis Cappel), exciting attention (Pareus, thus Louis Cappel). Come, namely, so that thou mightest hear the particular circumstances of those things which Christ had in general predicted to you, Matthew 24, so that all might all the more acknowledge through thee the wonderful providence of God concerning Jewish affairs (Grotius).
And I heard, etc.: And John heard one of the four living creatures speaking to him with a great and terrible voice, like the noise of thunder. Inviting him to come near, or to attend and see.
 Greek: Καὶ εἶδον ὅτε ἤνοιξε τὸ ἀρνίον μίαν ἐκ τῶν σφραγίδων, καὶ ἤκουσα ἑνὸς ἐκ τῶν τεσσάρων ζώων λέγοντος, ὡς φωνῆς βροντῆς, Ἔρχου καὶ βλέπε.  Greek: καὶ.  The Byzantine textual tradition favors ὅτι/that. However, the Textus Receptus, Codices Alexandrinus, Sinaiticus, and Ephræmi Rescriptus, and some Byzantine texts read ὅτε/when.  Genesis 1:5b: “…and the evening and the morning were the first (י֥וֹם אֶחָֽד׃, one day; ἡμέρα μία, in the Septuagint) day.”  Matthew 28:1: “In the end of the sabbath, as it began to dawn toward the first day of the week (εἰς μίαν σαββάτων, unto the one of sabbaths), came Mary Magdalene and the other Mary to see the sepulchre.”