Psalm 12:2

Everyone lies to his neighbor. They speak with flattering lips, and with a double heart.

Psalm 41:6

If he comes to see me, he speaks falsehood. His heart gathers iniquity to itself. When he goes abroad, he tells it.

Romans 16:18

For those who are such do not serve our Lord Christ, but their own belly; and by their smooth and flattering speech, they deceive the hearts of the innocent.

Psalm 10:7

His mouth is full of cursing, deceit, and oppression. Under his tongue is mischief and iniquity.

Jeremiah 9:8

Their tongue is a deadly arrow; it speaks deceit: one speaks peaceably to his neighbor with his mouth, but in his heart he lies in wait for him.

1 Chronicles 12:33

Of Zebulun, such as were able to go out in the army, who could set the battle in array, with all kinds of instruments of war, fifty thousand, and who could command and were not of double heart.

Psalm 5:9

For there is no faithfulness in their mouth. Their heart is destruction. Their throat is an open tomb; with their tongue they are deceitful.

Psalm 28:3

Do not draw me away with the wicked, with the workers of iniquity who speak peace with their neighbors, but mischief is in their hearts.

Psalm 144:8

whose mouths speak deceit, Whose right hand is a right hand of falsehood.

James 1:8

He is a double-minded man, unstable in all his ways.

Psalm 36:3-4

The words of his mouth are iniquity and deceit. He has ceased to be wise and to do good.

Psalm 38:12

They also who seek after my life lay snares. Those who seek my hurt speak mischievous things, and meditate deceits all day long.

Psalm 52:1-4

Why do you boast of mischief, mighty man? God's loving kindness endures continually.

Psalm 55:21

His mouth was smooth as butter, but his heart was war. His words were softer than oil, yet they were drawn swords.

Psalm 59:12

For the sin of their mouth, and the words of their lips, let them be caught in their pride, for the curses and lies which they utter.

Psalm 62:4

They fully intend to throw him down from his lofty place. They delight in lies. They bless with their mouth, but they curse inwardly. Selah.

Psalm 144:11

Rescue me, and deliver me out of the hands of foreigners, whose mouths speak deceit, whose right hand is a right hand of falsehood.

Proverbs 20:19

He who goes about as a tale-bearer reveals secrets; therefore do not keep company with him who opens wide his lips.

Proverbs 29:5

A man who flatters his neighbor spreads a net for his feet.

Jeremiah 9:2-6

Oh that I had in the wilderness a lodging place of wayfaring men; that I might leave my people, and go from them. For they are all adulterers, an assembly of treacherous men."

Ezekiel 12:24

For there shall be no more any false vision nor flattering divination within the house of Israel.

1 Thessalonians 2:5

For neither were we at any time found using words of flattery, as you know, nor a cloak of covetousness (God is witness),

Treasury of Scripture Knowledge

Summary

They speak vanity every one with his neighbour: with flattering lips and with a double heart do they speak.

A double heart

Bible References

Flattering

Psalm 5:9
For there is no faithfulness in their mouth. Their heart is destruction. Their throat is an open tomb; with their tongue they are deceitful.
Psalm 28:3
Do not draw me away with the wicked, with the workers of iniquity who speak peace with their neighbors, but mischief is in their hearts.
Psalm 62:4
They fully intend to throw him down from his lofty place. They delight in lies. They bless with their mouth, but they curse inwardly. Selah.
Proverbs 20:19
He who goes about as a tale-bearer reveals secrets; therefore do not keep company with him who opens wide his lips.
Proverbs 29:5
A man who flatters his neighbor spreads a net for his feet.
Ezekiel 12:24
For there shall be no more any false vision nor flattering divination within the house of Israel.
Romans 16:18
For those who are such do not serve our Lord Christ, but their own belly; and by their smooth and flattering speech, they deceive the hearts of the innocent.
1 Thessalonians 2:5
For neither were we at any time found using words of flattery, as you know, nor a cloak of covetousness (God is witness),

A double heart

1 Chronicles 12:33
Of Zebulun, such as were able to go out in the army, who could set the battle in array, with all kinds of instruments of war, fifty thousand, and who could command and were not of double heart.

General references

Genesis 29:19
Laban said, "It is better that I give her to you, than that I should give her to another man. Stay with me."
Judges 16:6
Delilah said to Samson, "Please tell me where your great strength lies, and how you can be bound and subdued."
Habakkuk 1:3
Why do you show me iniquity, and look at perversity? For destruction and violence are before me. There is strife, and contention rises up.
Acts 12:22
The people shouted, "The voice of a god, and not of a man."