The power of the tongue

Avoiding strife brings a man honor, but every fool is quarrelsome.
Proverbs 20:3

A gentle tongue is a tree of life; but perverseness therein is a breaking of the spirit.
Proverbs 15:4

Whoso keeps his mouth and his tongue keeps his soul from troubles.

Proverbs 21:23

Keep your tongue from evil and your lips from telling lies.

Psalms 34:13

Without wood a fire goes out; without a gossip a quarrel dies down.

Proverbs 26:20

When words are many, transgression is not lacking, but whoever restrains his lips is prudent.
Proverbs 10:19 

The tongue can bring death or life; those who love to talk will reap the consequences.
Proverbs 18:21

Those who consider themselves religious and yet do not keep a tight rein on their tongues deceive themselves, and their religion is worthless.
James 1:26

Set a guard over my mouth, LORD; keep watch over the door of my lips.
Psalm 141:3

Indeed, we all make many mistakes. For if we could control our tongues, we would be perfect and could also control ourselves in every other way.
James 3:2