An insight from tonight’s Bible study on Romans 4:
It’s not just that we can’t work our way to righteousness by perfect law-keeping. Moreover, the sort of relationship that comes by working is of a different kind from a relationship based on faith.
A servant works for wages, and the relationship depends on the work of the servant. A child is in a relationship prior to any behaviour on its part.
So although God does demand perfect law-keeping, He wants something even better than perfectly obedient servants: children who will allow Him to be their Father.