1 Peter 3:15
but reverence the Lord God in your hearts, and be always ready to answer every one that asks of you a reason for the hope that is in you, with meekness and fear;
Matthew 12:34
Generation of vipers, how can you, being evil, speak good things? For out of the abundance of the heart, the mouth speaks.
Titus 1:10-11
For there are many unruly and vain talkers and deceivers, especially those of the circumcision,
James 3:6-8
And the tongue is a fire, the world of iniquity. So is the tongue placed among our members, defiling the whole body, setting on fire the course of life, and being set on fire by hell.
2 Peter 2:18
For by speaking boastful words of folly, they allure through the lusts of the flesh, and through lasciviousness, those who had really escaped from those who live in error.