The Heart is Either Beliving In The TRUTH or it’s in deceit, astray.

Proverbs 23:26 (KJV)

My son, give me thine heart, and let thine eyes observe my ways.

Psalm 73:26 (KJV)

My flesh and my heart faileth: but God is the strength of my heart, and my portion for ever.

Psalm 37:4 (KJV)

Delight thyself also in the Lord: and he shall give thee the desires of thine heart.

Jeremiah 17:9 (KJV)

The heart is deceitful above all things, and desperately wicked: who can know it?

Matthew 6:21 (KJV)

For where your treasure is, there will your heart be also. 

Proverbs 4:23 (KJV)

Keep thy heart with all diligence; for out of it are the issues of life.