Matthew 15:18

But the things which proceed from the mouth come from the heart, and these defile the man.

Matthew 12:34

Offspring of vipers, how can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks.

Matthew 15:11

Not that which enters into the mouth, defiles the man; but that which proceeds out of the mouth that defiles the man.

James 3:6-10

And the tongue is a fire, the tongue is made a world of wickedness among our members, it defiles the whole body and sets on fire the course of nature and is set on fire by hell.

Luke 19:22

He said to him, Out of your mouth will I judge you, evil servant. You knew that I am an austere man, taking up what I laid not down, and reaping what I did not sow?

Revelation 13:5-6

And there was given him a mouth speaking great things and blasphemy, and power was given him to continue forty-two months [three years and a half].

Treasury of Scripture Knowledge

Summary

But those things which proceed out of the mouth come forth from the heart; and they defile the man.

Bible References

General references

Matthew 15:11
Not that which enters into the mouth, defiles the man; but that which proceeds out of the mouth that defiles the man.
Matthew 12:34
Offspring of vipers, how can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks.
Luke 19:22
He said to him, Out of your mouth will I judge you, evil servant. You knew that I am an austere man, taking up what I laid not down, and reaping what I did not sow?
James 3:6
And the tongue is a fire, the tongue is made a world of wickedness among our members, it defiles the whole body and sets on fire the course of nature and is set on fire by hell.
Revelation 13:5
And there was given him a mouth speaking great things and blasphemy, and power was given him to continue forty-two months [three years and a half].