Jeremiah Chapter 17 AMP (Amplified)
9 The heart is deceitful above all things, and it is exceedingly perverse {and} corrupt and severely, mortally sick! Who can know it [perceive, understand, be acquainted with his own heart and mind]?
10 I the Lord search the mind, I try the heart, even to give to every man according to his ways, according to the fruit of his doings.