1 Peter 3:15
But consecrate Christ in your hearts, as Lord. Be always in readiness to make and answer to any one who asks you a reason for the hope that is within you, yet with gentleness and reverence.
Matthew 12:34
"You generation of vipers! How can you speak good, when you are evil? For the mouth speaks what the heart is full of. "When the time of fruit drew near, he sent his slaves to the vine-dressers seized to get his fruit.
Titus 1:10-11
For there are many individuals who are unruly, empty talkers and deceivers, particularly those of the circumcision, whose mouths must be stopped;
James 3:6-8
And the tongue is a fire; it is a very world of iniquity among our members, defiling the whole body, and setting on fire the wheel of nature, and is itself set on fire by hell.
2 Peter 2:18
For speaking great swelling words of vanity, they entangle, by their lasciviousness, in the lusts of the flesh, those who are just about to escape from the men that live in misconduct.