I came across this recently in Piper’s book entitled Think. In principle, this seems to apply quite well to believers, particularly as we struggle to live under grace and not the Law.
In relation to Rom.10.2-3…
“They have a zeal for God, but not according to knowledge. For, being ignorant of the righteousness of God, and seeking to establish their own, they did not submit to God’s righteousness.”
Here is the root of their suicidal zeal for God. In all their thinking about God and his righteousness, they missed the main point – that it is a free gift for faith. When they seek to establish their own righteousness, they are not submitting to the righteousness of God. In fact, their effort to establish their own righteousness is rebellion and insubordination against the righteousness of God. This is why they are not saved.
But you can hear the zealous kinsmen of Paul cry out in defense: “Wait a minute! You do us entirely wrong. It is precisely our efforts to establish righteousness in our lives that is our submission to God’s righteousness. What else would subjection to God’s righteousness look like, except the zeal to establish righteousness in our lives so that it come into conformity to God’s righteousness? What would you want us to do – be indifferent to whether we are righteous or not?”
But Paul says that when you live this way – when you labor to show yourself righteous so that God will accept you – you are not submitting to God’s righteousness; you are in rebellion against God. Why? Because God’s righteousness is a gift of free and sovereign grace, not a merited attainment by human effort – or even a Spirit-wrought performance of relative success in holiness (sanctification). And since it is always and entirely a free gift, submission to it means receiving righteousness as a gift.
The way that gift comes is described in Rom.10.4 “For Christ is the end of the law for righteousness to everyone who believes.” All of God’s law was leading to Christ for righteousness for all who believe. By faith we receive Christ. And in Christ we have the righteousness of God. “For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God” (2Cor.5.21). This is what they were ignorant of, and therefore, Paul says, they had a zeal for God and were not saved.
…Paul’s kinsmen needed to see that the righteousness of God that they lacked was a free gift of that same grace. It comes only through union with Christ by faith. And when it comes, it brings in its train the power to love (Rom.13.8; Gal.5.6).