I Corinthians 12:
I Corinthians 12:9-11 (NIV)
“But 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. That is why, for Christ’s sake, I delight in weaknesses, in insults, in hardships, in persecutions, in difficulties. For when I am weak, then I am strong.”
It is in our weakness that God makes us strong. So we will always have challenges because it is in those times God wants us to lean on Him for strength.