1 John 5:16-17

If anyone sees his brother committing a sin that does not lead to death, he will pray and ask [on the believer’s behalf] and God will for him give life to those whose sin is not leading to death. There is a sin that leads to death; I do not say that one should pray for this [kind of sin]. All wrongdoing is sin, and there is sin that does not lead to death [one can repent of it and be forgiven].