Do not praise yourself

“Let another praise you, and not your own mouth; a stranger, and not your own lips.” (Prov. 27:2 ESV)

You are satisfied by the yield of your lips

“From the fruit of a man's mouth his stomach is satisfied; he is satisfied by the yield of his lips.” (Prov. 18:20 ESV)

Set a guard over your mouth

“Set a guard, O Lord, over my mouth; keep watch over the door of my lips!” (Psalm 141:3 ESV)

Make your speech judicious and persuasive  

“The heart of the wise makes his speech judicious and adds persuasiveness to his lips. Gracious words are like a honeycomb, sweetness to the soul and health to the body.” (Prov. 16:23-24 ESV)

The Word is near your mouth and heart

“But what does it say? “The word is near you, in your mouth and in your heart” (that is, the word of faith that we proclaim)” (Rom. 19:8 ESV)