'Sinning' in the Bible

Now, thus sinning against the brethren, and wounding their weak conscience, ye sin against Christ.

For what glory is it, if sinning and being buffeted ye shall bear it? but if, doing good and suffering, ye shall bear it, this is acceptable with God.

If any one see his brother sinning a sin not unto death, he shall ask, and he shall give him life, for those that do not sin unto death. There is a sin to death: I do not say of that that he should make a request.