Matthew 15:18

But the things that come out of the mouth come from the heart, and these defile the person.

Matthew 12:34

Offspring of vipers! How are you able to say good things [when you] are evil? For from the abundance of the heart the mouth speaks.

Proverbs 15:2

The tongue of the wise will dispense knowledge, but the mouth of fools will pour out folly.

Proverbs 15:28

A heart of righteousness will ponder the answer, but a mouth of wickedness will pour out deceit.

Matthew 15:11

It is not what goes into the mouth that defiles a person, but what comes out of the mouth--this defiles a person."

James 3:6-10

And the tongue [is] a fire! The world of unrighteousness, the tongue, is set among our members, defiling the whole body and setting on fire {the course of human existence}, being set on fire by hell.

1 Samuel 24:13

Just as the ancient proverb says, 'From the wicked, wickedness goes out,' but my hand will not be against you!

Psalm 36:3

The words of his mouth [are] wickedness and deceit. He has ceased to have insight [and] to do good.

Proverbs 6:12

A worthless man, an evil man, goes around with {deceitful speech}.

Proverbs 10:32

The lips of the righteous know [the] acceptable, but the mouth of the wicked, the perverse.

Luke 19:22

He said to him, '{By your own words} I will judge you, wicked slave! You knew that I am a severe man, withdrawing what I did not deposit and reaping what I did not sow.

Revelation 13:5-6

And a mouth was given to him speaking great [things] and blasphemies, and authority to act was given to him [for] 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
It is not what goes into the mouth that defiles a person, but what comes out of the mouth--this defiles a person."
Matthew 12:34
Offspring of vipers! How are you able to say good things [when you] are evil? For from the abundance of the heart the mouth speaks.
1 Samuel 24:13
Just as the ancient proverb says, 'From the wicked, wickedness goes out,' but my hand will not be against you!
Psalm 36:3
The words of his mouth [are] wickedness and deceit. He has ceased to have insight [and] to do good.
Proverbs 6:12
A worthless man, an evil man, goes around with {deceitful speech}.
Proverbs 10:32
The lips of the righteous know [the] acceptable, but the mouth of the wicked, the perverse.
Proverbs 15:2
The tongue of the wise will dispense knowledge, but the mouth of fools will pour out folly.
Luke 19:22
He said to him, '{By your own words} I will judge you, wicked slave! You knew that I am a severe man, withdrawing what I did not deposit and reaping what I did not sow.
James 3:6
And the tongue [is] a fire! The world of unrighteousness, the tongue, is set among our members, defiling the whole body and setting on fire {the course of human existence}, being set on fire by hell.
Revelation 13:5
And a mouth was given to him speaking great [things] and blasphemies, and authority to act was given to him [for] forty-two months.