In times of weakness we discover just how strong the strength of God is. This is a lesson God taught Paul by permitting Satan to afflict him with a “thorn in the flesh,” which the apostle repeatedly pleaded with God to remove. However, although Satan’s goal is always to kill and to destroy, God had certain plans to use that thorn to further the development of Christlike character in the apostle. God knew that Paul was susceptible to the pride of self-sufficiency and therefore he needed to learn that the strength of God was made perfect in His servant’s “weakness” (2 Cor. 12:9).
In addition to his own personal struggles, Paul faced severe treatment from others: “we are afflicted in every way, but not crushed; perplexed, but not despairing; persecuted, but not forsaken; struck down, but not destroyed; always carrying about in the body the dying of Jesus, so that the life of Jesus also may be manifested in our body” (2 Cor. 4:8–10). One might be tempted to think that this much suffering would result in a spirit of complaint and bitterness, but such was not the case with Paul.
Instead, he wrote to Timothy, “I thank Christ Jesus our Lord, who has strengthened me, because He considered me faithful, putting me into service” (1 Tim. 1:12). The secret to Paul’s strength was his inner reliance on Christ, who had not only called him into the ministry, but also promised to strengthen him to persevere to the end.
Faithful is He who calls you, and He also will bring it to pass. - 1 Thess. 5:24