Psalm 12:2

They will speak vanity each with his neighbor: smooth lips, with a heart and a heart will they speak

Psalm 41:6

And if he came to see, he will speak vanity: his heart will gather vanity to him; he will go forth without; he will speak.

Romans 16:18

For such serve not our Lord Jesus Christ, but their own belly; and by specious language and praise completely deceive the hearts of the innocent.

Psalm 10:7

His mouth was filled with cursing and deceit and violence: under his tongue, trouble and vanity.

Jeremiah 9:8

Their tongue a deadly arrow, speaking deceit; in his mouth he will speak peace to his neighbor, and be will lay his wait in his midst

1 Chronicles 12:33

From Zebulon coming forth to the army, setting the battle in array with all the utensils of war, fifty thousand to set in order, with not a heart and a heart.

Psalm 5:9

Not steadfast in his mouth; the midst of them mischiefs; their throat a grave opened; they will be smooth with their tongue,

Psalm 28:3

Thou wilt not draw me with the unjust, and with those working vanity, speaking peace with their neighbors, and evil in their heart

Psalm 144:8

Whom their mouth spake vanity, and their right hand a right hand of falsehood.

James 1:8

A man divided in opinion unsteady in all his ways.

Psalm 36:3-4

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

Psalm 38:12

My friends and my neighbors will stand from before my stroke, and my kindred stood from far off.

Psalm 52:1-4

To the overseer instruction to David: In the coming of Doeg the Edomite to Saul, and he will say to him, David came to the house of Ahimelech. Why wilt thou boast in evil, thou strong one? the mercy of God is all the day.

Psalm 55:21

They were divided from the wrath of his mouth, and his heart drew near: his words were soft above oil, and they drawn swords.

Psalm 59:12

The sin of their mouth the word of their lips, and they shall be taken in their pride: and from cursing and from falsehood they will recount.

Psalm 62:4

Surely they counseled to thrust down his lifting up: they will delight in falsehood: with their mouth they will praise, and in their inward parts they will curse. Silence.

Psalm 144:11

Snatch me away and deliver me from the hand of the sons of the stranger, whom their mouth spake vanity, and their right hand a right hand of falsehood:

Proverbs 20:19

He revealing a secret going about tale-bearing: and thou shalt not intermingle with him embracing his lips.

Proverbs 29:5

A man making smooth against his neighbor spreads a net for his steps.

Jeremiah 9:2-6

Who will give me in the desert a lodging-place of travelers? and I will leave my people and go from them, for they all commit adultery; an assembly of those acting faithlessly.

Ezekiel 12:24

For no more shall there be any vain vision and smooth divination in the midst of the house of Israel.

1 Thessalonians 2:5

For neither once in word were we flatterers, as ye know, neither in a pretext of covetousness; God the 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
Not steadfast in his mouth; the midst of them mischiefs; their throat a grave opened; they will be smooth with their tongue,
Psalm 28:3
Thou wilt not draw me with the unjust, and with those working vanity, speaking peace with their neighbors, and evil in their heart
Psalm 62:4
Surely they counseled to thrust down his lifting up: they will delight in falsehood: with their mouth they will praise, and in their inward parts they will curse. Silence.
Proverbs 20:19
He revealing a secret going about tale-bearing: and thou shalt not intermingle with him embracing his lips.
Proverbs 29:5
A man making smooth against his neighbor spreads a net for his steps.
Ezekiel 12:24
For no more shall there be any vain vision and smooth divination in the midst of the house of Israel.
Romans 16:18
For such serve not our Lord Jesus Christ, but their own belly; and by specious language and praise completely deceive the hearts of the innocent.
1 Thessalonians 2:5
For neither once in word were we flatterers, as ye know, neither in a pretext of covetousness; God the witness:

A double heart

1 Chronicles 12:33
From Zebulon coming forth to the army, setting the battle in array with all the utensils of war, fifty thousand to set in order, with not a heart and a heart.

General references

Genesis 29:19
And Laban will say, Good for me to give her to thee rather than for me to give her to another man. Dwell with me.
Judges 16:6
And Delilah will say to Samson, Announce now to me in what is thy great strength, and in what thou shalt be bound to humble thee.
Habakkuk 1:3
Wherefore wilt thou cause me to see vanity and cause me to look at labor? and oppression and violence before me, and there will be contention, and strife will be raised up.
Acts 12:22
And the people called aloud, The voice of God, and not of man.