Read Psalm 64:6 Using Other Translations
They search out iniquities; they accomplish a diligent search: both the inward thought of every one of them, and the heart, is deep.
They search out injustice, saying, "We have accomplished a diligent search." For the inward mind and heart of a man are deep!
As they plot their crimes, they say, “We have devised the perfect plan!” Yes, the human heart and mind are cunning.