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, Rev 16:18). 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 own, and not now revealed to men.