'Sinning' in the Bible

Thus, sinning against the brothers, and wounding their conscience when it is weak, you sin against Christ.

He who sins is of the devil, for the devil has been sinning from the beginning. To this end the Son of God was revealed, that he might destroy the works of the devil.

If anyone sees his brother sinning a sin not leading to death, he shall ask, and God will give him life for those who sin not leading to death. There is a sin leading to death. I don't say that he should make a request concerning this.