Ephesians 4:29
Let no corrupt word come out of your mouth; but what is good to useful edification, that it may benefit the hearers.
Matthew 12:35-37
A good man out of the good treasure of the heart produceth good things; and a wicked man out of the wicked treasure uttereth wicked things:
Colossians 4:6
Let your speech be always with grace, seasoned with discretion to know how ye ought to answer every one.
Titus 1:10-11
For there are many disorderly persons, vain-talkers and deceivers, especially those of the circumcision; whose mouths must be stopped:
James 3:6-9
And the tongue is a fire, a world of iniquity: so is the tongue among our several parts, defiling the whole body, inflaming the course of nature, and is set on fire by hell.
Romans 10:14-15
But how shall they call upon him in whom they have not believed? and how shall they believe on him of whom they have not heard? and how shall they hear without a preacher?
2 Corinthians 2:16
to these indeed we are an odor of death to death; to those an odor of life unto life. And who is sufficient for these things?
2 Corinthians 11:15
It is therefore no great thing, if his ministers also be transformed into ministers of righteousness; whose end shall be according to their works.
2 Peter 2:18
For when they speak swelling words of vanity, they ensnare in the lusts of the flesh, through their lasciviousness, those who had indeed withdrawn from such as deal in error;