Now to the one working, the wage is not reckoned according to grace, but according to debt. But the one not working, indeed who believes upon the One Who justifies the ungodly, his faith is reckoned unto righteousness (Romans 4:4–5)
Grace does not consider whether a person could or could not earn something; it is given solely on the basis of the desire of the one giving it. Therefore, to the one who thinks that he must work to earn or maintain his salvation, all he is doing is incurring a debt. However, to the one who believes that God is the One who justifies the ungodly, his faith is counted to him as righteousness. We are saved by grace through faith—by believing that Christ died for our sins, was buried, and rose again on the third day, according to the Scriptures—not by works that we have done, but according to His mercy.