Paul had a weakness he didn’t like in his life. The Bible doesn’t say what it was. Paul called it a thorn in the flesh. God used that weakness or flaw in Paul’s life to glorify His name.
2 Corinthians 12:
5 That experience is worth boasting about, but I’m not going to do it. I will boast only about my weaknesses. 6 If I wanted to boast, I would be no fool in doing so, because I would be telling the truth. But I won’t do it, because I don’t want anyone to give me credit beyond what they can see in my life or hear in my message, 7 even though I have received such wonderful revelations from God. So to keep me from becoming proud, I was given a thorn in my flesh, a messenger from Satan to torment me and keep me from becoming proud.
8 Three different times I begged the Lord to take it away. 9 Each time he said, “My grace is all you need. My power works best in weakness.” So now I am glad to boast about my weaknesses, so that the power of Christ can work through me. 10 That’s why I take pleasure in my weaknesses, and in the insults, hardships, persecutions, and troubles that I suffer for Christ. For when I am weak, then I am strong.