1 Corinthians 2:11
Is there anyone who can understand his own thoughts except his own inner spirit? In the same way, no one can know the thoughts of God except God's Spirit.
Proverbs 20:27
A person's spirit is the lamp of the LORD; it searches throughout one's innermost being.
Jeremiah 17:9
"The heart is more deceitful than anything. It is incurable who can know it?
Proverbs 14:10
The heart knows its own bitterness an outsider cannot share in its joy.
Proverbs 20:5
The intentions of a person's heart are deep waters, but a discerning person reveals them.
Romans 11:33-34
O how deep are God's riches, and wisdom, and knowledge! How unfathomable are his decisions and unexplainable are his ways!
1 Corinthians 2:10
But God has revealed those things to us by his Spirit. For the Spirit searches everything, even the deep things of God.