KJV:
And he said unto me, My grace is sufficient for thee: for my strength is made perfect in weakness. Most gladly therefore will I rather glory in my infirmities, that the power of Christ may rest upon me.
NASB:
And He has said to me, "My grace is sufficient for you, for power is perfected in weakness." Most gladly, therefore, I will rather boast about my weaknesses, so that the power of Christ may dwell in me.