Romans 8:26 – 28
New International Version (NIV)
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 through wordless groans. 27 And he who searches our hearts knows the mind of the Spirit, because the Spirit intercedes for God's people in accordance with the will of God.
28 And we know that in all things God works for the good of those who love him, who have been called according to his purpose.
From BibleGateway.com: http://www.biblegateway.com/passage/?search=Romans+8.26-28&version=NIV