1 Corinthians 2:9-11

This is why the Scriptures say: Things never discovered or heard of before, things beyond our ability to imagine — these are the many things God has in store for all his lovers. But God now unveils these profound realities to us by the Spirit. Yes, he has revealed to us his inmost heart and deepest mysteries through the Holy Spirit, who constantly explores all things. After all, who can really see into a person’s heart and know his hidden impulses except for that person’s spirit? So it is with God. His thoughts and secrets are only fully understood by his Spirit, the Spirit of God.