Colossians 4:6
Let your speech be alway with grace, seasoned with salt, that ye may know how ye ought to answer every man.

Ephesians 4:29
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.

James 3:10
Out of the same mouth proceedeth blessing and cursing. My brethren, these things ought not so to be.

Matthew 12:35-36
A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.

But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment.