In 1 Corinthians 2:10, NIV, ..God has revealed it to us by his spirit.
1 Corinthians 2:6-16
[6]Yet I do proclaim a message of wisdom to those who are spiritually mature. But it is not the wisdom that belongs to this world or to the powers that rule this world — powers that are losing their power.
[7]The wisdom I proclaim is God’s hidden wisdom, which he had already chosen for our glory even before the world was made.
[8]None of the rulers of this world knew this wisdom. If they had known it, they would not have crucified the Lord of glory.
[9]However, as the scripture says: “What no one ever saw or heard, what no one ever thought could happen, is the very thing God prepared for those who love him.”
[10]But it was to us that God made known his secret by means of his Spirit. The Spirit searches everything, even the hidden depths of God’s purposes.
[11]It is only the spirit within people that knows all about them; in the same way, only God’s Spirit knows all about God.
[12]We have not received this world’s spirit; instead, we have received the Spirit sent by God, so that we may know all that God has given us.
[13]So then, we do not speak in words taught by human wisdom, but in words taught by the Spirit, as we explain spiritual truths to those who have the Spirit.
[14]Whoever does not have the Spirit cannot receive the gifts that come from God’s Spirit. Such people really do not understand them; they are nonsense to them, because their value can be judged only on a spiritual basis.
[15]Whoever has the Spirit, however, is able to judge the value of everything, but no one is able to judge him.
[16]As the scripture says: “Who knows the mind of the Lord? Who is able to give him advice?”We, however, have the mind of Christ.