Rom 6:12 Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof.
Define sin.
God has given us a physical, mental and spiritual body. We need to look after all aspects.
Joh 2:21 But he spake of the temple of his body.
1Co 6:19-20
19 What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own? 20 For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.
If you are destroying the body you are not glorifying God.
You asked for a definition of sin.
There are two definitions given in the scripture.
The early Jewish definition is disobedience to the law.
The second definition of sin is the definition that Paul gave to the Gentiles.
Galatians 5:16-24
But I say, walk by the Spirit, and you will not carry out the desire of the flesh.
For the desire of the flesh is against the Spirit, and the Spirit against the flesh;
for these are in opposition to one another, in order to keep you from doing whatever
you want. But if you are led by the Spirit, you are not under the Law. Now
the deeds
of the flesh are evident, which are: sexual immorality, impurity, indecent behavior,
idolatry, witchcraft, hostilities, strife, jealousy, outbursts of anger, selfish ambition,
dissensions, factions, envy, drunkenness, carousing, and things like these, of which
I forewarn you, just as I have forewarned you, that those who practice such things
will not inherit the kingdom of God. But the fruit of the Spirit is love, joy, peace, patience,
kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law.
Now those who belong to Christ Jesus crucified the flesh with its passions and desires.
So clearly, the most exhaustive definition of sin involves the passions and desires of the
flesh. And they are self evident.
Your no stranger to Paul's definition of sin in Galatians 5.
But wait there's more, "
factions, envy, drunkenness, carousing, and things like these"
It is clear that Paul never gave the Gentiles a simple list of rules to follow.
Paul defined sin as anything that is not of faith in Jesus Christ.