²⁶ In the same way, the Spirit helps us in our weakness. We do not know what we ought to pray for, but the Spirit himself intercedes for us with groans that words cannot express. ²⁷ And he who searches our hearts knows the mind of the Spirit, because the Spirit intercedes for the saints in accordance with God’s will.

 ¹⁰ but God has revealed it to us by his Spirit.

   The Spirit searches all things, even the deep things of God. ¹¹ For who among men knows the thoughts of a man except the man’s spirit within him? In the same way no one knows the thoughts of God except the Spirit of God.

From BibleGateway.com: http://www.biblegateway.com/passage/?search=1 Corinthians 2:10-11&version=NIV1984