To keep me from becoming conceited because of these surpassingly great revelations, there was given me a thorn in my flesh, a messenger of satan, to torment me. Three times I pleaded with the Lord to take it away from me. 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 the 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."
My power is made perfect
in weakness, says the Lord
Paul was tormented with his affliction and pleaded with God to remove it, just as we endure long-suffering and can not see an end to our trial. Remember what the Lord said to Paul. "My grace is sufficient for you", what you cannot do on your own, I will bring you through.
My strength comes from God, not my own ability. By admitting our weakness we are affirming God's strength.