Proverbs 4: 23-24 ESV

“Keep your heart with all vigilance, for from it flow the springs of life. Put away from you crooked speech, and put devious talk far from you.”

Keep careful watch for dangers that could potentially enter your heart, because “…from the heart the mouth speaks. (Luke 6:34 NIV)

If your heart is tainted then your words will be
tainted and will not bring life, as God intended your words to do.