Sin is the transgression of a law, yea of a good law, yea of God’s law. Sin
presupposes that there is a law in being, for where is no law there is no
transgression (Romans 4.15). But where there is sin, there is a law, and a
transgression of the law. Whosoever committeth sin transgresseth also the law, for
sin is a transgression of the law (I John 3.4). That this is the sin intended in our
text is apparent from Romans 7.7.
Now the law not only forbids the doing of evil, whether by thought, word or deed,
but also commands the doing of good. So to omit the good commanded is sin, as
well (or ill) as is the doing of the evil that is forbidden. Against the fruit of the Spirit
there is no law, but against the works of the flesh (for the antithesis holds) there is
law, for they are all against the law, as the Apostle tells us (Galatians 5.19-24).
Whatever, then, transgresses the law of God–in whole or in part (James 2.10)–is
therefore and therein a sin, whether it break an affirmative or a negative precept
i.e. whether it is the omission of good or the commission of evil.