1 Corinthians 2:11
For what man knows the things of the man, except the spirit of the man in him? And so nobody knows the things of God except the Spirit of God.
Proverbs 20:27
The spirit of man is the lamp of LORD, searching all his innermost parts.
Jeremiah 17:9
The heart is deceitful above all things, and it is exceedingly corrupt. Who can know it?
Proverbs 14:10
The heart knows its own bitterness, and a stranger does not intermeddle with its joy.
Proverbs 20:5
Purpose in the heart of man is deep water, but a man of understanding will draw it out.
Romans 11:33-34
O the depth of wealth, both of the wisdom and the knowledge of God! How unsearchable are his judgments, and his ways beyond finding out!
1 Corinthians 2:10
But God disclosed it to us through his Spirit, for the Spirit searches all things, even the deep things of God.