Jamieson, Fausset and Brown on 2 Corinthians 12:7

7. exalted above measure--Greek, "overmuch uplifted." How dangerous must self-exaltation be, when even the apostle required so much restraint! [Bengel].

abundance--Greek, "the excess"; exceeding greatness.

given ... me--namely, by God (Job 5:6; Php 1:29).

thorn in the flesh--(Nu 33:55; Eze 28:24). Alford thinks it to be the same bodily affliction as in Ga 4:13, 14. It certainly was something personal, affecting him individually, and not as an apostle: causing at once acute pain (as "thorn" implies) and shame ("buffet": as slaves are buffeted, 1Pe 2:20).

messenger of Satan--who is permitted by God to afflict His saints, as Job (Job 2:7; Lu 13:16).

to buffet me--In Greek, present: to buffet me even now continuously. After experiencing the state of the blissful angels, he is now exposed to the influence of an evil angel. The chastisement from hell follows soon upon the revelation from heaven. As his sight and hearing had been ravished with heavenly "revelations," so his touch is pained with the "thorn in the flesh."