Thorn in the Flesh

Paul describes a "thorn in his flesh":

2 Corinthians 12:7 (New King James Version) The Thorn in the Flesh

7 And lest I should be exalted above measure by the abundance of the revelations, a thorn in the flesh was given to me, a messenger of Satan to buffet me, lest I be exalted above measure.

http://www.merriam-webster.com/dictionary/buffet describes "buffett" as:

Date: 13th century
1 : a blow especially with the hand
2 : something that strikes with telling force

We aren't told what it is that is such a burden on him. He describes this condition after he has told of the vision of heaven. He also tells us that God allows him to carry this cross, to keep him humble.

2 Corinthians 12:5 Of such a one I will boast; yet of myself I will not boast, except in my infirmities. 6 For though I might desire to boast, I will not be a fool; for I will speak the truth. But I refrain, lest anyone should think of me above what he sees me to be or hears from me.7 And lest I should be exalted above measure by the abundance of the revelations, a thorn in the flesh was given to me, a messenger of Satan to buffet me, lest I be exalted above measure. 8 Concerning this thing I pleaded with the Lord three times that it might depart from me. 9 And He said to me, “My grace is sufficient for you, for My strength is made perfect in weakness.” Therefore most gladly I will rather boast in my infirmities, that the power of Christ may rest upon me. 10 Therefore I take pleasure in infirmities, in reproaches, in needs, in persecutions, in distresses, for Christ’s sake. For when I am weak, then I am strong.

So great will be the Kingdom of God.