This familiar passage is a difficult passage. Many suffering Christians have tried in all sincerity to follow the instructions given here, yet have not been healed. This may be because the promise has a specific, rather than general, application.
First, “is anyone afflicted?” This word means “troubled,” referring especially to persecution or deprivation. For such a person, the admonition is: “Let him pray.” Assuming that he is right with God, and is praying in His will (1 John 5:14,15), he can expect either the needed relief or the needed grace.
Secondly: “Is there one who is sick?” Here the Greek word actually refers to physical illness. However, the context shows that this particular sickness has come specifically “since (the true connotation of if) he have committed sins.” There are “many weak and sickly” believers who have so persistently refused to judge and confess their sins (1 Corinthians 11:30-32) that the Lord finally has laid them aside with sickness or injury. The remedy is for such a person to call for the church elders (not the reverse), and “let them pray” (after he has first openly confessed and repented of his sins) in faith anointing him with oil. then the promise is that, if the elders themselves have faith and are right with God, the Lord will forgive his sins and raise him up.
Furthermore, their prayer of faith will “save the sick.” The Greek word in this case means “wearied,” rather than “ill,” and it tells us that the sinner has been delivered from the heavy burden of guilt which had wearied his soul, as well as the illness which had weakened his body. There are other reasons for illness besides unrepented sin, when other courses of action are indicated, but this is a wonderful promise of both spiritual and physical healing when sin is the problem. - HMM