1 Corinthians 2:10-14 NIV
these are the things God has revealed to us by his Spirit.
The Spirit searches all things, even the deep things of God. For who knows a person’s thoughts except their own spirit within them? In the same way no one knows the thoughts of God except the Spirit of God. What we have received is not the spirit of the world, but the Spirit who is from God, so that we may understand what God has freely given us. This is what we speak, not in words taught us by human wisdom but in words taught by the Spirit, explaining spiritual realities with Spirit-taught words. The person without the Spirit does not accept the things that come from the Spirit of God but considers them foolishness, and cannot understand them because they are discerned only through the Spirit.
NIV: New International Version