Notice that I said “Why rules don’t work.” I did not say “Why rules are not good.” I think rules are good. I think they are helpful, but they never work to bring about lasting change?
Why? Because they are external.
John Owen, in Indwelling Sin, say, “A law proposed unto us is not to be compared, for efficacy, to a law inbred in us.”*
This is why Gentiles “do instinctively the things of the Law … [showing ] the work of the Law written in their hearts.” (Romans 2:14-15). It is internal.
This is why Israel’s grand hope in the New Covenant is that God writes a new law on their hearts (Jeremiah 31:33). External law exacerbated sin; it did not cure it.
This is why external walls can modify behavior but cannot change the life.
Too many Christians are into behavior modification. “Stop … Start.” But we too often fail to address the heart.
Heart issues always show up. If we fix one problem area, it will simply show up in another area. For lasting change, we must kill the root. And that can only be done by internal change.
So let us, as those committed to making disciples, be more worried about the why than the what.
*The Complete Works of John Owen, 6:165