Matthew 15:18

But the things going forth out of the mouth come from the heart, and these pollute the man.

Matthew 12:34

O generation of vipers! how can ye speak good things, being evil? for out of the abundance of the heart the month speaks.

Proverbs 15:2

The tongue of the wise will make knowledge good: and the mouth of the foolish will gush forth folly.

Proverbs 15:28

The heart of the just one shall meditate to answer: and the mouth of the unjust shall gush out evil.

Matthew 15:11

Not that coming into the mouth pollutes the man; but that going forth out of the mouth, this pollutes the man.

James 3:6-10

(And the tongue a fire, a world of iniquity: so the tongue is placed in our members, defiling the whole body, and burning the wheel of creation; and burned by hell.

1 Samuel 24:13

As the ancient parable will say, Injustice will go forth from the unjust; and my hand shall not be upon thee.

Psalm 36:3

The words of his mouth vanity and deceit: he ceased to be circumspect, to do good.

Proverbs 6:12

A man of Belial, a man of iniquity, goes with perverseness of mouth.

Proverbs 10:32

The lips of the just one shall know acceptance: and the mouth of the unjust, perverseness.

Luke 19:22

And he said to him, Out of thy month will I judge thee, O evil servant. Thou knewest that I am an austere man, taking up what I laid not down, and reaping what I sowed not:

Revelation 13:5-6

And a mouth was given him speaking great things and blasphemies; and power was given him to make war forty-two months.

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 coming into the mouth pollutes the man; but that going forth out of the mouth, this pollutes the man.
Matthew 12:34
O generation of vipers! how can ye speak good things, being evil? for out of the abundance of the heart the month speaks.
1 Samuel 24:13
As the ancient parable will say, Injustice will go forth from the unjust; and my hand shall not be upon thee.
Psalm 36:3
The words of his mouth vanity and deceit: he ceased to be circumspect, to do good.
Proverbs 6:12
A man of Belial, a man of iniquity, goes with perverseness of mouth.
Proverbs 10:32
The lips of the just one shall know acceptance: and the mouth of the unjust, perverseness.
Proverbs 15:2
The tongue of the wise will make knowledge good: and the mouth of the foolish will gush forth folly.
Luke 19:22
And he said to him, Out of thy month will I judge thee, O evil servant. Thou knewest that I am an austere man, taking up what I laid not down, and reaping what I sowed not:
James 3:6
(And the tongue a fire, a world of iniquity: so the tongue is placed in our members, defiling the whole body, and burning the wheel of creation; and burned by hell.
Revelation 13:5
And a mouth was given him speaking great things and blasphemies; and power was given him to make war forty-two months.