1 John 3:10

3:10 By this the children of God and the children of the devil are revealed: Everyone who does not practice righteousness – the one who does not love his fellow Christian – is not of God.

1 John 5:16

5:16 If anyone sees his fellow Christian committing a sin not resulting in death, he should ask, and God will grant life to the person who commits a sin not resulting in death. There is a sin resulting in death. I do not say that he should ask about that.