Is it ever permissible to pray for the death of a believer caught in sin?
No. Scripture teaches that no believer or church body has the right to pray for the death of an erring believer; it is never permissible. While a sin unto death exists and God may take an erring believer home, that judgment belongs solely to God, not to His people.
Les explains from Galatians 6:1 that if a man is taken in a fall, those who are spiritual are to restore such a one in the spirit of meekness, lest even church leaders be taken in just as great a sin. He says all are human and prone to fall. Then John delineates that some sins would not cause God to take a believer out of physical life, but some He will. Les says he has seen a believer refuse to come away from a sinful lifestyle, and after being dealt with, suddenly a heart attack or car accident takes them. God takes them home lest they keep bringing reproach to His name. This is the sin unto death. John says, "I do not say that you shall pray for it." In other words, no believer or church body ever has the right to pray for the death of an erring believer. That is never permissible; it is in God's hands.
If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it.
More Questions
What is the sin unto death that John says not to pray for?
According to John's epistle there is a sin unto death, and John warns that you should not pray for it.
Do believers who commit the sin unto death lose their salvation?
Believers who commit the kind of deep, open sin that God removes from physical existence by death do not lose their salvation—Scripture says God takes them out of their physical existence, but they are still saved.