Verses with the word liars in the Old Testament (4 verses):

Deuteronomy 33:29
Happy art thou, O Israel: who is like unto thee, O people saved by the LORD, the shield of thy help, and who is the sword of thy excellency! and thine enemies shall be found liars unto thee; and thou shalt tread upon their high places.

Psalms 116:11
I said in my haste, All men are liars.

Isaiah 44:25
That frustrateth the tokens of the liars, and maketh diviners mad; that turneth wise men backward, and maketh their knowledge foolish;

Jeremiah 50:36
A sword is upon the liars; and they shall dote: a sword is upon her mighty men; and they shall be dismayed.