“If anyone sees his brother committing a sin not leading to death, he shall ask, and God will for him give life to those who commit sin not leading to death. There is a sin leading to death; I do not say that he should make request for this. All unrighteousness is sin, and there is a sin not leading to death” (1 Joh 5:16-17). It is always appropriate to pray for one another, even when a fellow believer has committed a sin.