2 Corinthians 12:8-9 (New International Version)

8Three times I pleaded with the Lord to take it away from me. 9But he said to me, "My grace is sufficient for you, for my power is made perfect in weakness." Therefore I will boast all the more gladly about my weaknesses, so that Christ's power may rest on me.

From BibleGateway.com: http://www.biblegateway.com/passage/?search=2 corinthians 12:8-9&version=NIV