People have often wondered what St. Paul's "thorn in the flesh" was, that he prayed three times should be healed, but God said instead, "My grace is sufficient for you, for My strength is made perfect in weakness." (see II Corinthians 12:7-10)
Well, I may be all wrong, and if so I hope someone will correct me, but recently this sentence by St. Paul struck me. He's writing to the Galatians (4:15): "I bear you witness that, if possible, you would have plucked out your own eyes and given them to me."
Apparently he had weak eyesight?
We know he wasn't blind, because we have the very moving story in Acts 9 of how he was struck blind on the road to Damascus, but then received his sight again (just re-reading it chokes me up):
10 Now there was a certain disciple at Damascus named Ananias; and to him the Lord said in a vision, “Ananias.”
And he said, “Here I am, Lord.”
11 So the Lord said to him, “Arise and go to the street called Straight, and inquire at the house of Judas for one called Saul of Tarsus, for behold, he is praying. 12 And in a vision he has seen a man named Ananias coming in and putting his hand on him, so that he might receive his sight.”
13 Then Ananias answered, “Lord, I have heard from many about this man, how much harm he has done to Your saints in Jerusalem. 14 And here he has authority from the chief priests to arrest all who call on Your name.”
15 But the Lord said to him, “Go, for he is a chosen vessel of Mine to bear My name before Gentiles, kings, and the children of Israel. 16 For I will show him how many things he must suffer for My name’s sake.”
17 And Ananias went his way and entered the house; and laying his hands on him he said, “Brother Saul, the Lord Jesus, who appeared to you on the road as you came, has sent me that you may receive your sight and be filled with the Holy Spirit.” 18 Immediately there fell from his eyes something like scales, and he received his sight at once; and he arose and was baptized.
(I have actually known someone who was legally blind and was instantly healed after his parents, one a Pentecostal Christian and the other a Jew, prayed before the Iveron Icon of the Mother of God.)
So we know St. Paul could see, but from his letter to the Galatians, it seems he couldn't see very well, and they loved him so dearly they would have given them their own eyes. Maybe that was his "thorn in the flesh."
If so, it would indeed fulfill the humbling function St. Paul ascribes to it, to remind him of how he had been struck blind in the first place, and why. It was a constant reminder that he had persecuted the churches and delivered many Christians to death.
But more than that, if this guess is right, the weak eyesight shows you and me and the whole world something else very important. Namely, that what happened to this man on the road to Damascus was real. It was no hallucination or guilty imagination run wild or any such thing. He really was struck blind, and never fully recovered from it, but bore the sign both of his guilt and of his forgiveness and conversion all his life long. "My strength is made perfect in weakness," says the Lord. Indeed!