1 Peter 3:15
but sanctify the Lord Christ in your hearts: being always ready for an answer to every one asking you a reason for the hope which is in you, but with meekness and fear:
Matthew 12:34
O ye generations of vipers, how are you, being evil, able to speak good things? for out of the abundance of the heart the mouth speaks.
Titus 1:10-11
For many are incorrigible, speaking vain things and egotistical, especially those from the circumcision,
James 3:6-8
The tongue, a fire, the world of iniquity: the tongue sits down in the midst of our members, and corrupting the whole body, and setting on fire the course of nature; and it is set on fire from hell.
2 Peter 2:18
For speaking swelling words of vanity, in the lusts of the flesh they beguile with their impurities, those that have but partially escaped, who are still moving about in their delusion;