Sin mentioned in 1 John 5:16; in this verse John discourages prayer for those who sin in this way. Most likely, John was speaking of those who decisively turn their backs upon the truth, as well as those false teachers who deceive the church (Heb 6:4–6; 2 Jn 1:7–9).
Sin unto Death
From Tyndale Bible Dictionary, adapted by Mission Mutual. CC BY-SA 4.0.