PSALMS 34:13

13keep your tongue from evil and your lips from speaking lies.

PROV 13:3

3He who guards his lips guards his life, but he who speaks rashly will come to ruin.

PROV 21:23

23He who guards his mouth and his tongue keeps himself from calamity.

MATT 12:36-37

36But I tell you that men will have to give account on the day of judgment for every careless word they have spoken. 37For by your words you will be acquitted, and by your words you will be condemned."

JAMES 1:26

26If anyone considers himself religious and yet does not keep a tight rein on his tongue, he deceives himself and his religion is worthless

JAMES 3:5-18

5Likewise the tongue is a small part of the body, but it makes great boasts. Consider what a great forest is set on fire by a small spark. 6The tongue also is a fire, a world of evil among the parts of the body. It corrupts the whole person, sets the whole course of his life on fire, and is itself set on fire by hell.7All kinds of animals, birds, reptiles and creatures of the sea are being tamed and have been tamed by man, 8but no man can tame the tongue. It is a restless evil, full of deadly poison.9With the tongue we praise our Lord and Father, and with it we curse men, who have been made in God's likeness. 10Out of the same mouth come praise and cursing. My brothers, this should not be. 11Can both fresh water and saltA water flow from the same spring? 12My brothers, can a fig tree bear olives, or a grapevine bear figs? Neither can a salt spring produce fresh water.13Who is wise and understanding among you? Let him show it by his good life, by deeds done in the humility that comes from wisdom. 14But if you harbor bitter envy and selfish ambition in your hearts, do not boast about it or deny the truth. 15Such "wisdom" does not come down from heaven but is earthly, unspiritual, of the devil. 16For where you have envy and selfish ambition, there you find disorder and every evil practice. 17But the wisdom that comes from heaven is first of all pure; then peace-loving, considerate, submissive, full of mercy and good fruit, impartial and sincere. 18Peacemakers who sow in peace raise a harvest of righteousness.

I PETER 3:10

10For, "Whoever would love life and see good days must keep his tongue from evil and his lips from deceitful speech.