How do we know what sin is? How do we know what’s right and what’s wrong? We all respond as if some actions are good and some are evil, but why do we respond the way we do? How do we know?
Because we’re all made in God’s image, we can’t help but react as if good and evil exist; this is built right into our DNA. And it’s perfectly natural to make up our own definitions, to decide for ourselves what’s right and wrong.
But deciding for ourselves what’s good or evil actually contradicts the very concept of good and evil. Claiming something is good or evil means it is so regardless what anyone else thinks about it; we know this instinctively, it’s rooted in the very claim. But if we can decide for ourselves what good and evil are, then everyone else can too, and then it is all just a matter of opinion, contradicting the very essence of what we know intrinsically to be true.
So if good and evil really do exist, then it isn’t a matter of opinion, yours or mine or anyone else’s; not even governments can define morality. If an action is truly good or evil, then it can only be so because some divine Being says so. There can be no other basis for morality.
This is why Scripture says we can’t know what sin is apart from God’s Law: Torah. (Ro 7:7) It’s only through Torah that we can correctly identify sin (Ro 3:20); and any alteration of Torah corrupts the divine standard of righteousness, and thus the very definition of sin. (De 4:2)
Our old man understands Torah as God’s eternal law and rejects it (Ro 8:7), departing from the light of Torah (Is 8:20), loving darkness instead. (Jn 3:19) Those breaking any of God’s laws violate Torah as a whole (Ja 2:10), and are the least in God’s kingdom. (Mt 5:19) But our new man delights in Torah (Ro 7:22); it lights our way (Ps 119:105), for Torah is light. (Pr 6:23)
Who dares presume the right to decide which of God’s laws are no longer relevant? (Ps 119:6) What standard would they use to judge God’s Law like this? (Ja 4:11) How can a finite being prove any of God’s Laws aren’t eternally good? (Ps 119:152) Torah is timeless. (Ps 119:160)
To sin is to break Torah (1Jn 3:4a), for sin is defined as breaking Torah. (4b) We hide Torah in our heart that we might not sin against God (Ps 119:11), for all who err from Torah as a manner of life will be trodden down, exposed as deceitful and false. (Ps 119:118) The nature of God’s children is that we keep His commands. (1Jn 2:3)