Psalm 32 says, Blessed is he whose fault is taken away, whose sin is covered.
Paul in Romans wanted the believers to know the price that was paid for our salvation was unrepayable and how God views our sins. Abraham believed God and it was credited to him as righteousness. When we work at our jobs, the boss pays us. It is not a gift from our boss, it is what is due to us for work that we provided. When we received the gift of salvation from God it is not a wage that is given to us because we did a job but it is our faith that is credited as righteousness.
Jesus warned the disciples that the hypocrisy of the Pharisees proves this point. They are like yeast to bread dough. It totally infiltrates the dough. Jesus warned us that all of the things we do that we think no one knows about will one day be revealed. The Pharisees were great at the “outward spirituality” but their “inward spirituality” was very dark and evil. We serve a God who cares about us and as insignificant as a little brown sparrow is, God cares for them, so how much more does He care for us. We are worth more than a small sparrow.