(3) And lest I should be exalted above measure through the abundance of the revelations, there was given to me (f) a thorn in the flesh, the messenger of (g) Satan to buffet me, lest I should be exalted above measure.
(3) An excellent doctrine: why God will have even his best servants to be vexed by Satan, and by every type of temptations: that is, lest they should be too much puffed up, and also that they may be made perfect by being continually exercised in them.
(f) He means sinful lust, that sticks fast in us as it were a thorn, to such a degree that it forced Paul himself who was regenerated to cry out, "I do not that good that I would", etc. And he calls it a thorn by a metaphor taken from thorns, or stumps, which are very dangerous and harmful for the feet, if a man walks through woods that are cut down.
(g) Which sets those lusts on fire.