The Greek noun stoma (στόμα) means mouth, but by extension refers to speech, voice, words, or the edge of a sword. It appears about 78 times in the NT and carries both literal and metaphorical significance.
Stoma (mouth) is the instrument of confession, prophecy, praise, and judgment in Scripture. 'For with the heart one believes and is justified, and with the mouth (stomati) one confesses and is saved' (Romans 10:10) — salvation is a mouth-event, a public declaration. Jesus declared that 'out of the overflow of the heart the mouth speaks' (Matthew 12:34) — the mouth reveals the inner person. The sword of the Spirit is 'the word of God' and Christ's weapon is 'the sword of his mouth' (Revelation 1:16; 19:15) — His stoma is the instrument of both word and judgment. Fulfilling prophecy, Jesus opened his mouth to teach (Matthew 5:2). In Acts, Jesus promised His disciples: 'I will give you words and wisdom that none of your adversaries will be able to resist or contradict' (Luke 21:15).