An organ designed by God to receive and prepare food for the stomach, also, in humans, for speaking. All speech should result in praise to Him. (Ps 34:1; 51:15; 71:8; 145:21) The psalmist declared that everything that has breath will praise Jehovah; therefore humans must use their mouths to do this if they desire to live. The apostle Paul explains that belief in God and his Son, even believing with the heart, is not enough. It has to be accompanied by public declaration in order to bring salvation.​—Ps 150:6; Ro 10:10.

In harmony with his purpose and his right and power as Creator, Jehovah can put the proper words into the mouth of his servant. In the case of his prophets, he did so miraculously, by inspiration. (Ex 4:11, 12, 15; Jer 1:9) In one instance he caused even a dumb animal, an ass, to speak. (Nu 22:28, 30; 2Pe 2:15, 16) Today God’s servants can have his words in their mouths, not by inspiration, but from his inspired written Word, which equips them completely for every good work. (2Ti 3:16, 17) They no longer have to wait for Christ to come to provide the good news, nor do they need to go to some other source for what they preach. They have it right before them, ready for them to speak, as they are told: “The word is near you, in your own mouth and in your own heart.”​—Ro 10:6-9; De 30:11-14.

Can Bring Life or Death. It follows that the proper use of the mouth is vital, and so Jehovah declares it to be. His Word says: “The mouth of the righteous one is a source of life.” (Pr 10:11) The mouth, therefore, has to be guarded most carefully (Ps 141:3; Pr 13:3; 21:23), for stupid misuse of it can bring its owner to ruin. (Pr 10:14; 18:7) God holds a person accountable for what he brings forth from his mouth. (Mt 12:36, 37) A person may speak hastily, making a rash vow. (Ec 5:4-6) He may flatter another, to that person’s overthrow and his own condemnation. (Pr 26:28) It is especially important to guard one’s mouth when before the wicked, because a slight deviation from what God’s wisdom directs his servant to say can bring reproach on God’s name and may cause that one’s death. (Ps 39:1) Jesus gave a fine example of submissiveness to God’s will without complaint or any reviling of his wicked opposers.​—Isa 53:7; Ac 8:32; 1Pe 2:23.

The Christian must exercise constant vigilance, for he is imperfect; therefore he needs to watch his heart. Jesus said that it is not what goes into the mouth that defiles a man, but what comes forth from the mouth, for “out of the abundance of the heart the mouth speaks.” (Mt 12:34; 15:11) Thus one must be careful not to let anything come forth from the mouth without thought, without considering the consequences. This requires that the person use his mind to apply the good things learned from God’s Word.​—Pr 13:3; 21:23.

 Since the power of the mouth is great for good or bad, when Jehovah guides the mouth great results are attained. He made Isaiah’s mouth “like a sharp sword” and the words in Jeremiah’s mouth “a fire.” Jehovah backed up their prophetic words by his power, and they came true. (Isa 49:2; Jer 5:14) On the other hand, it is dangerous to listen to anything that comes out of the mouth of a person known to be an apostate; it can bring a person to ruin.​—Pr 11:9.

Figurative Use. God represents himself symbolically as having a mouth. None of his pronouncements are uttered to no purpose, in vain; they will be fulfilled to the smallest detail. (Isa 55:10, 11) Therefore, those who desire life must live by every word proceeding from his mouth. (De 8:3; Mt 4:4) When on earth his Son Jesus Christ conformed his whole life to his Father’s words and now has universal authority granted him. As King appointed by Jehovah, he will strike the earth with “the rod of his mouth.” (Isa 11:4) The vision of Revelation shows him smiting the nations with a long sword proceeding out of his mouth. (Re 19:15, 21) This figure of speech evidently represents the authority he will exercise in command of all Jehovah’s heavenly armies in ordering and supervising the warfare that results in the execution of God’s enemies.

“Mouth” is often used synonymously for speech or the power of speech, as can be seen from some of the instances cited above. The rule governing evidence in a case under the Mosaic Law, and also followed in the Christian congregation, is that a person may be found guilty only “at the mouth,” that is, on the testimony, of two or three witnesses. (De 17:6; Mt 18:16; compare 2Co 13:1.) A few other examples of similar usage are found at Job 32:5; Psalms 10:7; 55:21; 78:36; Ezekiel 24:27; 29:21; Luke 21:15, ftn; Romans 15:6.

In addition, “mouth” may have reference to the opening of something, such as of a well (Ge 29:2), a bag (Ge 43:12; 44:1, 2), a cave (Jos 10:22), or to an opening in the earth (Nu 16:32), as well as to the ability of the earth to absorb liquids poured onto it (Ge 4:11). Sheol, mankind’s common grave, is spoken of as having a wide mouth, so as to receive many dead.​—Isa 5:14.

The Palate. The palate is the roof of the mouth, which separates the mouth from the nasal cavities; it has a soft part that forms a curtain between the mouth and the pharynx. In the Scriptures, “palate” is, in some cases, used synonymously with “mouth.”​—Pr 8:7; Ho 8:1, ftn.

Both Job and Elihu make a comparative use of the word when they liken the palate’s ability to discriminate taste to man’s judgment as to what is right and wise. (Job 12:11; 34:3) That the palate has a function in tasting is not erroneous, as is sometimes claimed. This can be seen by observing the part played by the palate in swallowing. Food is pressed by the tongue against the palate and spread out as it moves back into the pharynx, which is a cone-shaped tube leading toward the stomach and connecting also with the nasal passages. This brings about better diffusion of the aroma of the food into the nasal passages, which greatly contributes to what is commonly called taste.