Psalms
Set a watch, O LORD, before my mouth; keep the door of my lips.
Proverbs
He that keepeth his mouth keepeth his life: but he that openeth wide his lips shall have destruction.
A soft answer turneth away wrath: but grievous words stir up anger.
The heart of the righteous studieth to answer: but the mouth of the wicked poureth out evil things.
A fool uttereth all his mind: but a wise man keepeth it in till afterwards.
Matthew
For by thy words thou shalt be justified, and by thy words thou shalt be condemned.
Ephesians
Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.
Neither filthiness, nor foolish talking, nor jesting, which are not convenient: but rather giving of thanks.
Colossians
Let your speech be always with grace, seasoned with salt, that ye may know how ye ought to answer every man.
James
Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath:
If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man's religion is vain.