Now to him who works, the wages are not counted as grace but as debt. David Celebrates the Same Truth But to him who does not work but believes on Him who justifies the ungodly, his faith is accounted for righteousness,
If you work for righteousness, you are paying off a sin debt.
Here, we see that there is another way to righteousness, that is, through belief in what God tells you.
I don't know why this is - its just God's design.
Blessed is the man to whom the Lord shall not impute sin.”
God's offers forgiveness which is right-standing/righteousness in His books.