'In Sin' in the Bible

Our rejoicing is this: the testimony of our conscience, that in singleness of heart and with godly pureness - and not in fleshly wisdom, but by the grace of God - we have had our conversation in the world, and most of all to you-wards.

how that the abundance of their rejoicing is, that they are tried with much tribulation. And thereto, though they were exceeding poor, yet have they given exceeding richly, and that in singleness.

Did I therein sin, because I submitted myself, that ye might be exalted? And because I preached unto you the Gospel of God freely?