(peh, chekh, garon (Ps 149:6); Aramaic pum, tera (Da 3:26); stoma, 71 times, once logos, i.e. "word of mouth," "speech" (Ac 15:27); once we find the verb epistomizo, "to silence," "to stop the mouth" (Tit 1:11)):
The "mouth" denotes language, speech, declaration (compare "lips," "tongue," which see): "By the mouth of" is "by means of," "on the declaration of" (Lu 1:70; Ac 1:16); "Whoso killeth any person, the murderer shall be slain at the mouth of witnesses" (Nu 35:30; compare De 17:6; Mt 18:16; Heb 10:28); "I will give you mouth and wisdom" (Lu 21:15); "fool’s mouth" (Pr 18:7).
"Mouth" also denotes "spokesman": "He shall be to thee a mouth" (Ex 4:16).
MOUTH. The principal Hebrew words are peh, translated “mouth,” but also “language,” “corner,” “edge,” “skirt,” and any opening, such as of a well (Gen.29.2), of a sack (Gen.42.27), of a cave (Josh.10.22), or of a grave (Ps.141.7); and hēkh, translated “mouth” and “roof of the mouth” (Job.29.10). In the NT stōma is translated “mouth” except in the idiomatic “face to face” (lit., “mouth to mouth,” 2John.1.12; 3John.1.14), and “edge [lit., mouth] of the sword” (Heb.11.34).
The way in which the Bible constantly uses the organ of speech in the sense of “language” is a good example of the employment of the concrete for the abstract. Silence is the laying of the hand on the mouth (Job.40.4), freedom of speech is the enlarged mouth (Eph.6.19). So to receive a message is to have words put into the mouth (Jer.1.9). Humiliation is the mouth laid in the dust (Lam.3.29; niv “bury his face in the dust”).
Finally, the mouth is personified; it is an independent agent. It brings freewill offerings (Ps.119.108). God sets a watch before it (Ps.141.3); it selects food (Prov.15.14), uses a rod (Prov.14.3), and has a sword (Rev.19.15). This personification helped to contribute to the Jewish idea of the Angel of the Lord and the voice of the Lord and prepared the way for the “word made flesh” (John.1.14).——JBG
In addition, the word “mouth” is used fig. to refer to an entrance, such as cave’s mouth (Josh 10:27), grave’s mouth (Ps 141:7), sack’s mouth (Gen 42:27), and well’s mouth (29:10). It is used metaphorically to refer to the absolute sovereignty of God in the fiat of His words in judgment, as in the phrases “rod of his mouth” (Isa 11:4) and “out of his mouth goeth a sharp sword” (Rev 19:15).
B. J. Anson, “Mouth,” EBr (1963), XV, 908; P. E. Adolph, Missionary Health Manual (1964), 126, 127.