Revelation 10:3

"Seven thunders uttered their voices." The seven thunders uttering their voices signify, the Holy Spirit of sevenfold power, who through the prophets announced all things to come, and by His voice John gave his testimony in the world; but because he says that he was about to write the things which the thunders had uttered, that is, whatever things had been obscure in the announcements of the Old Testament; he is forbidden to write them, but he was charged to leave them sealed, because he is an apostle, nor was it fitting that the grace of the subsequent stage should be given in the first. "The time," says he, "is at hand."45 For the apostles, by powers, by signs, by portents, and by mighty works, have overcome unbelief. After them there is now given to the same completed Churches the comfort of having the prophetic Scriptures subsequently interpreted, for I said that after the apostles there would be interpreting prophets.

For the apostle says: "And he placed in the Church indeed, first, apostles; secondly, prophets; thirdly, teachers,"46 and the rest. And in another place he says: "Let the prophets speak two or three, and let the others judge."47 And he says: "Every woman that prayeth or prophesieth with her head uncovered, dishonoureth her head"48 And when he says, "Let the prophets speak two or three, and let the others judge," he is not speaking in respect of the Catholic prophecy of things unheard and unknown, but of things both announced and known. But let them judge whether or not the interpretation is consistent with the testimonies of the prophetic utterance.49 It is plain, therefore, that to John, armed as he was with superior virtue, this was not necessary, although the body of Christ, which is the Church, adorned with His members, ought to respond to its position.

And he cried out with a loud voice, as when a lion roars. And it is said that the holy angel of wrath was symbolically represented as having roared like a lion, signifying the judgment against the impious.

And when he said, "he cried out," the seven thunders uttered their voices. The seven thunders refer to the seven ministering spirits whose memory has been mentioned earlier; therefore, it is placed after the article. He says, "the seven thunders," referring to those seven spirits to which the reference pertains. What then is the meaning of the seven spirits crying out? It is that they also fully correspond with the punishments inflicted upon sinners, offering a grateful hymn of praise to God, acknowledging that all things have been done justly. At the same time, the one who cried out clarified the various forms of punishments.

[The loud voice] indicates that through his servants he was proclaimed faithfully and with strength. As the prophet says, "And he made firm the glory of his strength." "When he called out, the seven thunders sounded." Because of the known use of the number seven, I think that the seven thunders signify the various manners of the church's preaching. The apostle Paul spoke of this concerning his service to others, "As babes in Christ, I fed you with milk, not solid food," however to others, "solid food is for the perfect," yet also to others, "avoid the heretical man after the first and second admonition." Therefore, the church is said to proclaim rightly through its usual offices of preaching.

And when he cried out, the seven thunders uttered their voices. When the Lord preaches mightily, the Church, also full of sevenfold grace, raises its voices to preach. For the lion roars, who will not fear? The Lord God has spoken, who will not prophesy (Amos III)? For the seven thunders are the same as the seven trumpets of which he speaks.

And he cried with a loud voice as when a lion roareth. Just as the lion's cry inspires beasts with fear, so does Christ inspire beastlike men with fear by threatening through the holy preachers, according to this: The lion roareth, who will not fear? [Variant of Amos 3:8] And when he had cried, the seven thunders spoke their voices. The seven thunders signify the same thing as the lion's voice, namely the preaching of the Word, as in The voice of thy thunder in a wheel. [Ps. 76:19] Note also that the seven thunders are said to have spoken after the lion's voice because the sevenfold Spirit also taught the apostles to preach what the Lord taught, whence they are called the sons of thunder. [Mark 3:17] They spoke their voices because the holy doctrine does not receive the fables of the Jews or the rubbish of philosophers into its dogmas. However, a very complicated question arises for us in what is said after that: And I was about to write the things which the seven thunders spoke: and I heard a voice from heaven, saying: Seal up the things which the seven thunders have spoken; and write them not. If the holy preaching had not been written, how would it have come to us? It seems therefore that we should understand in this place only a specific kind of writing; for one should know that the reason why we shut something under seal is in order that it should not be open to all, but that it may be loosed in due time for those we trust; whereas what we write openly, we bring to the knowledge of all. Therefore we are ordered not to divulge the mysteries of God's words to everyone indiscriminately, but to supply them with measure and as though from under a seal, according to how able we see people are to receive them; and we are ordered to give milk to drink to some people, and solid food to others. [Ref. to 1 Cor. 3:1-2] The divine mysteries are also shut under a protective seal in order that they should not be disclosed to people who were not going to believe in them at all, because when they do not accept them, they start laughing at them.