The Law commands, what? Love. At it's essence, God's Law commands love. That is something that is found in the heart and which ripples out through the actions. This goes beyond mere outward deeds and gets right down to the very motivations behind what we do and how we interact with others.
What do you do when you see that you fail? What, as a Christian, do you do? Well, one of the purposes of the Law is to show you that you are guilty and need a savior. So, even as a Christian, the Law is intended to show you that you still need Jesus, you still need grace. You aren't now some superman.
But this answer is not satisfactory to most of us. The fear is that we will abuse grace -we will use grace as a context to minimize the grievous nature of our sin. The fear may be real. We may actually abuse grace. Or it may be more hypothetical. We are afraid of grace that free. We are used to operating within the safe but cruel confines of performance-based living, complete with the hope of self-redemption and the biting sting and grinding pressure of condemnation. We essentially say to ourselves, "You don't deserve grace because you will abuse it, so I'm putting you back under the Law to punish you and teach you a lesson."
Let me illustrate what I mean. Let's say there is a man who was taught always that "real Christians" give 10% of their money to church faithfully. Now, there is nothing wrong with that, so don't miss the point. But this person frets and worries because he finds himself in predicaments often where he cannot afford to pay the amount he predetermined. He also has to eat and pay rent. He feels guilty, blaming his mismanagement of money. How dare he buy things for himself, for example, or do something fun with his wife!
So, he turns to Dave Ramsey out of guilt. He may tell himself that he wants to do right by the Lord, but this goal is mixed heavily with a desire to wipe away his sense of guilt and condemnation. Dave Ramsey's advice just makes him feel worse, because he has a difficult time even doing that. So what does he do?
He runs to his Bible. He reads about Ananias and Sapphira. He reads about sacrificial giving. He reads about cheerful giving. He looks at himself and at his heart and is terrified and depressed. He is not cheerful -he is stressed about it! And because he "mismanaged" his money by spending it on a few personal things that month, he concludes he is selfish. He then wonders if he should force himself to starve for a few weeks so that he can just pay the tithe and get it over with. But he sees the lack of love and other-centeredness in his motivations there and just feels worse.
Where to turn now? He wants to turn back to the treadmill of the Law, so back to the Dave Ramsey website... and the cycle continues. Guilt, trying to pull up his bootstraps, failure, guilt, condemnation, more trying to pull up his bootstraps, etc. And at the end, he is not left with a heart that feels more loving and cheerful for giving. He is left with a heart that feels condemned and defeated... and exhausted.
Where is Jesus in all of this? Jesus stands not as Savior but as disappointed Lawgiver, shaking his head at how this poor man can't just get it together.
The thing is... the Law will do its job. It will show you that you fail, eventually. And it will eventually show you that you need a savior. But who will that savior be? Will it be you or will it be Jesus? Will it send you back on yourself, in the endless cycle of performance and guilt and shame, falling into a deeper pit because you see that living under the Law does not and cannot change your heart? Or will it send you to Jesus, to see the One who suffered, the pure One who was killed by your sins and for your sins, the one who gave and gave and gave to you in you poverty until it killed Him, and thus to see that you are free from your condemnation for something like poor stewardship, and thus to live in that freedom and go to Dave Ramsey out of that?