Treasury of Scripture Knowledge
They speak vanity every one with his neighbour: with flattering lips and with a double heart do they speak.
A double heart
For no faith may be put in their words; their inner part is nothing but evil; their throat is like an open place for the dead; smooth are the words of their tongues.
Do not take me away with the sinners and the workers of evil, who say words of peace to their neighbours, but evil is in their hearts.
Their only thought is to put him down from his place of honour; their delight is in deceit: blessing is in their mouths but cursing in their hearts. (Selah.)
He who goes about talking of the business of others gives away secrets: so have nothing to do with him whose lips are open wide.
A man who says smooth things to his neighbour is stretching out a net for his steps.
For there will be no more false visions or smooth use of secret arts in Israel.
For such people are not servants of the Lord Christ, but of their stomachs; and by their smooth and well-said words the hearts of those who have no knowledge of evil are tricked.
1 Thessalonians 2:5
For it is common knowledge among you that we never made use of smooth-sounding false words, and God is witness that at no time were we secretly desiring profit for ourselves,
A double heart
1 Chronicles 12:33
Of Zebulun, there were fifty thousand men, who went out with the army, expert in ordering the fight, to give help with all sorts of arms; true-hearted men.
And Laban said, It is better for you to have her than another man: go on living here with me.
So Delilah said to Samson, Make clear to me now what is the secret of your great strength, and how you may be put in bands and made feeble.
Why do you make me see evil-doing, and why are my eyes fixed on wrong? for wasting and violent acts are before me: and there is fighting and bitter argument.
And the people, with loud cries, said, It is the voice of a god, not of a man.