Sin is defined in Strong's dictionary as an offence and rests on the concept of missing the mark (G264). Interwoven in the concept is to err, to offend or to trespass.
In general, this is not a bad definition, however, it leaves man drifting on an island where you know you cannot reach the required standard by effort and hence it positions you into a perpetual cycle of sinning and repenting (which is good).
In Romans 8, Paul has an in-depth discussion of life in the flesh and life in the spirit.
For the new creation, living in the flesh would be regarded as a sin and the 'goal' subtly moves from keeping a law or a precept to living in Christ, and not in the flesh.
The concept of living in the spirit has as its core to find the place where God is, Christ, and to live there, as opposed to keeping laws and precepts. This allows for the child of God to meet the moral requirements of God's character, which was codified by the Laws of Moses.
It has now become possible to have as a guiding post, the character of Christ, as opposed to having to rely solely on the codified character of God as found in the Laws of Moses. Jesus highlighted the difference between the codified character of God as set out in the Laws of Moses and the character of God when He said that if a man that desires a woman that is not his wife, that man commits adultery, whilst the law required you to not commit physical adultery through an illicit act to comply.