In most cases, "mouth" in the Bible represents thought and logic, especially the kind of active, concrete thought that is connected with speech. The reason for this is pretty obvious, but it also holds when people, for instance, remove a stone from the mouth of a well, which represents gaining access to spiritual ideas. The mouth is used for eating as well as speaking, of course. In those circumstances, it represents our first, most external perception of a new spiritual idea or desire. This also makes sense, mirroring the way tasting food in the mouth gives us an instant impression of the quality of the food.

'Voice' signifies what is announced from the Word. 'Voice' often refers and is applied to things that cannot have a voice, as in Exodus 4, Nahum 3:2, Psalms 93:3-4.

A 'voice' signifies annunciation, and in a positive sense, annunciation from the Word, which is called 'the voice of Jehovah,' as is shown in Psalms 29:3-9 and Psalms 68:33, where 'voice' denotes divine truth, so the Word and annunciation from it.

'Voice' signifies the quality of interior things.

'Voice,' as in Revelation 19, signifies joy in worship, confession, and celebration of the Lord.

'A great voice heard in heaven,' as in Revelation 12:10, signifies the joy of the angels of heaven from the light and wisdom.

'A great voice,' as in Revelation 16:1, signifies the divine command.

'A great voice out of the temple of heaven,' as in Revelation 16:17, signifies a manifestation from the Lord out of the inmost of heaven.

'A great voice,' as in Revelation 21:3, signifies speech proceeding from love.

'One voice,' as in Revelation 9:13, signifies a divine command.

(Odkazy: Apocalypse Explained 16, 19; Arcana Coelestia 6971; Psalms 93, 93: 3-4)