Augustine of Hippo, on 1John 5:16

“He that knoweth his brother to sin a sin which is not to death, let him ask, and life shall be given to him, who sinneth not to death. There is a sin unto death: for that I say not that any man ask.”

“But what presses harder upon the present question is that saying of the apostle John, "If any man know that his brother sinneth a sin not unto death, he shall ask, and the Lord will give life to that man who sinneth not unto death: but there is a sin unto death: not for that do I say that he should ask." For it manifestly shows that there are some "brethren" whom we are not commanded to pray for, whereas the Lord bids us pray even for our persecutors. Nor can this question be solved except we acknowledge, that there are some sins in brethren that are worse than the sin of enemies in persecuting.”

Imported from an open dataset — not yet checked against the printed edition.