In Revelation 14:2, 'the voice of great thunder' signifies the Lord speaking through the New Heaven from Divine Love; it also signifies a glorification of the Lord from His celestial kingdom. (Apocalypse Revealed 615, Apocalypse Explained 855)

'Voices,' 'lightnings,' and 'thunders,' as in Revelation 16:18, signify rationalizations, falsifications of truth, and arguments grounded in falsities that stem from evil in the church among people who believe in salvation by faith alone. (Apocalypse Explained 821[4], 1014)

(Referências: Apocalypse Revealed 710)

855. And as the voice of a great thunder, signifies glorification of the Lord from His celestial kingdom. This is evident from the signification of "voice," as being glorification of the Lord, as above; also from the signification of "a great thunder," as being glorification of the Lord from His celestial kingdom. "Thunder" signifies glorification from the celestial kingdom, because from it only sounds, and not expressions of speech, are heard; and for the reason that all who are in that kingdom speak from love, that is, from affection, which is of the heart; and when such speech flows down from that heaven toward the regions below it is heard as thunder. For all affections in the spiritual world are heard as sounds with their variations, but the thoughts therefrom become manifested by the articulations of sound which are called words. (On this see above, n. 323, 393; and in the work on Heaven and Hell 234-245.) But all who are in the spiritual kingdom speak from thought, which belongs to the understanding or soul; and when such speech flows down out of heaven towards the regions below it is heard either as a voice or as harmonious music, or is seen before the eyes like the brightness of a cloud or like the flash of lightning before thunder. This is why "lightnings, thunders, and voices," signify in the Word enlightenment, understanding, and perception (See above, n. 273, 702, 704; and why voices let down from the celestial kingdom are heard as thunders (n. 353, 393, 821).