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.
All Commentaries on 1 John 5:16 Go To 1 John 5
Tertullian of Carthage
AD 220
But John, too, will teach us: "If any knoweth his brother to be sinning a sin not unto death, he shall request, and life shall be given to him; "because he is not "sinning unto death "this will be remissible. "(There) is a sin unto death; not for this do I say that any is to request".
For (in making these assertions) he was looking forward to the final clause of his letter, and for that (final clause) he was laying his preliminary bases; intending to say, in the end, more manifestly: "If any knoweth his brother to be sinning a sin not unto death, he shall make request, and the Lord shall give life to him who sinneth not unto death. For there is a sin unto death: not concerning that do I say that one should make request."