Question: where in the bible does it talk about the tongue being evil?
Answer: Proverbs 12:18 - "There is one whose rash words are like sword thrusts, but the tongue of the wise brings healing." As Children of God, our tongues have a lot of power. Proverbs 18:21 confirms this by saying, "Death and life are in the power of the tongue, and those who love it will eat its fruits."