Watch your tongue and keep your mouth shut, and you will stay out of trouble.
Proverbs 21:23 (NLT)

And a tiny rudder makes a huge ship turn wherever the pilot wants it to go, even though the winds are strong.
James 3:4 (TLB)

So also the tongue is a small thing, but what enormous damage it can do. A great forest can be set on fire by one tiny spark.
James 3:5 (TLB)

Avoid worthless, foolish talk that only leads to more godless behavior.
II Timothy 2:16 (NLT)

A gossip goes around telling secrets, but those who are trustworthy can keep a confidence.
Proverbs 11:13 (NLT)

If you claim to be religious but don’t control your tongue, you are fooling yourself, and your religion is worthless.
James 1:26 (NLT)

Let the words of my mouth, and the meditation of my heart, be acceptable in Thy Sight, O Lord, my strength, and my Redeemer.
Psalm 19:14 (KJV)