1 Samuel 16:7

But the Lord said to Samuel, “Do not look on his appearance or on the height of his stature, because I have rejected him. For the Lord sees not as man sees: man looks on the outward appearance, but the Lord looks on the heart.”

Jeremiah 17:10

“I the Lord search the heart and test the mind, to give every man according to his ways, according to the fruit of his deeds.”

Psalm 51:10

Create in me a clean heart, O God, and renew a right spirit within me.