Let’s examine the context of the passage. One of the reasons Paul wrote his second inspired letter to Corinth was to defend himself against the slanderous accusations of some in Corinth who had accused him of being a false apostle and false teacher (2 Cor. 10-13). One of the ways he did so was by listing the hardships he had undergone for Christ as an apostle and missionary (11:16-33). He also pointed out that he had received “visions and revelations of the Lord”(12:1).
Among these was his account of “a man” who, fourteen years prior, “was caught up to the third heaven – whether in the body or out of the body I do not know, God knows” (12:2). This man “was caught up into paradise…and heard things that cannot be told, which man may not utter” (12:3-4). Even though Paul spoke of this man in a way that distinguished him from Paul himself (12:5), I personally believe the man to be Paul himself, and his description of the man being caught up into Paradise where he heard unmentionable things an account of the time in which Paul had been stoned at Lystra, and in my opinion likely killed and subsequently resurrected (Acts 14:19-20).
It would be no small thing for a human being to have been given the privilege to see and hear things from the afterlife. Such an occurrence might lead to one becoming arrogant and conceited since he could count himself among “the privileged few” to have experienced such a thing. With this in mind, notice what Paul wrote next:
2 Corinthians 12:7-10 (ESV)
7 So to keep me from becoming conceited because of the surpassing greatness of the revelations, a thorn was given me in the flesh, a messenger of Satan to harass me, to keep me from becoming conceited.
8 Three times I pleaded with the Lord about this, that it should leave me.
9 But he said to me, “My grace is sufficient for you, for my power is made perfect in weakness.” Therefore I will boast all the more gladly of my weaknesses, so that the power of Christ may rest upon me.
10 For the sake of Christ, then, I am content with weaknesses, insults, hardships, persecutions, and calamities. For when I am weak, then I am strong.
No one knows for sure what this “thorn in the flesh” was. Was it Paul’s eyesight problems (implied in Galatians 4:15 and 6:11)? Was it a different physical disability, perhaps an injury left over from his stoning at Lystra? When one remembers that physical maladies are at times attributed to Satan (Job 2:7; Lk. 13:16), Paul calling his thorn “a messenger of Satan” certainly makes sense. On the other hand, contextually he had been defending himself from those who had been slandering him at Corinth. Anyone who has been lied about and slandered certainly knows the burden and torment which can come from that. Personally, I believe his thorn in the flesh was the false teachers who were lying about him. There’s no way to know for sure in any case on this side of heaven.
Regardless of what the thorn was, Paul wrote to Corinth that he had “pleaded with the Lord” to remove it from him “three times” (12:8). Yet the only answer he received from the Lord was this statement: “My grace is sufficient for you, for my power is made perfect in weakness” (12:9). Let us consider what this statement means.
God’s grace saves us from an eternity in hell (Tit. 2:11-12; Eph. 2:8). From eternity’s perspective, being in hell forever without end far outweighs any hardship or tribulation one experiences in this life. In like manner, spending eternity — time without end — in heaven with God in a place where there is no sorrow or pain far outweighs the hardships one goes through in this comparatively brief period which is our lives (cf. James 4:14). By saying “My grace is sufficient for you” to Paul, the Lord was helping the apostle to have the proper perspective about his burden.
Furthermore, think of all the people whom you highly respect, those who have the most patience, grace, maturity, and wisdom. I guarantee you that not a one of them has attained those highly valued qualities outside of undergoing hardships and trials of varying difficulty throughout their life, and learning from them to grow in the qualities they now have which you so admire and aspire towards yourself. When the Lord told Paul, “My power (dynamis, strength) is made perfect (teleioo, made complete, made mature) in weakness” (12:9), he was reminding Paul of a basic facet of human life: the experiences of life which make one weak and bring one down oftentimes can cause one to grow stronger in the end, if allowed. Struggles, hardships, bad times, persecutions, trials, tribulations…all of these have a way of making us stronger and more mature spiritually and bringing us closer to God (cf. Heb. 12:3-13).
Upon realizing this, Paul changed his perspective (12:9-10). Now he was glad he had his weaknesses and burdens which he figuratively called his “thorn in the flesh.” He now knew it was through them that he had the power and strength of Jesus, leading him to conclude, “For when I am weak, then I am strong” (12:10).