Revelation 10:3

“And cried with a loud voice, etc.] That all might hear, and to show earnestness and affection, and that it was a matter of great importance, as well as to denote the certainty of it; what he said is not expressed, but seems to be the book of prophecy, or what regarded the state of his church and kingdom, in the several periods of time to the blowing of the seventh trumpet, when the kingdoms of this world shall become his: and this voice of his was as [when] a lion roareth; loud and terrible; and indeed it was the voice of the lion of the tribe of Judah, which was heard far and near, throughout the whole world, by his people, and is terrible to his enemies: and when he had cried, seven…”

“as . . . lion--Christ, whom the angel represents, is often so symbolized (Rev 5:5, "the Lion of the tribe of Juda"). seven thunders--Greek, "the seven thunders." They form part of the Apocalyptic symbolism; and so are marked by the article as well known. Thus thunderings marked the opening of the seventh seal (Rev 8:1, Rev 8:5); so also at the seventh vial (Rev 16:17-18). WORDSWORTH calls this the prophetic use of the article; "the thunders, of which more hereafter." Their full meaning shall be only known at the grand consummation marked by the seventh seal, the seventh trumpet (Rev 11:19), and the seventh vial. uttered their--Greek, "spake their own voices"; that is, voices peculiarly their…”

“And cried with a loud voice, as when a lion roareth - The lion is the monarch of the woods, and his roar is an image of terror. The point of the comparison here seems to be the loudness with which the angel cried, and the power of what he said to awe the world - as the roar of the lion keeps the dwellers of the forest in awe. What he said is not stated; nor did John attempt to record it. Prof. Stuart supposes that it was “a loud note of woe, some interjection uttered which would serve to call attention, and at the same time be indicative of the judgments which were to follow.” But it is not necessary to suppose that this particular thing was intended. Any loud utterance - any solemn command…”

“And he cried - Uttering the words set down, Rev 10:6. And while he cried, or was crying - At the same instant. Seven thunders uttered their voices - In distinct words, each after the other. Those who spoke these words were glorious, heavenly powers, whose voice was as the loudest thunder. Revelation 10:4”

“loud: Pro 19:12; Isa 5:29, Isa 31:4, Isa 42:13; Jer 25:30; Joe 3:16; Amo 1:2, Amo 3:8 seven: Rev 8:5, Rev 14:2, Rev 15:1, Rev 15:7 Revelation 10:4”