Now to him who works, the wages are not counted as grace but as debt. But to him who does not work but believes on Him who justifies the ungodly, his faith is accounted for righteousness (Rom 4:4-5).

“These words present to us mysterious and strange governing principles in the Kingdom of Christ. Unworthy ones are excluded from grace simply because they count themselves worthy of merit. The pronouncements of the Kingdom of heaven sometimes seem to be contrary to human reasoning. Why? Our Lord said, ‘The Son of man came to save the lost.’ The fact that God gave his only Son as a blood sacrifice for us is the reason that he cannot tolerate self-righteousness. Contrariwise he adopts and justifies the most unworthy sinner if he will believe in the Son…As long as a person tries to accomplish his own merit he is striving against the grace of God. But the moment that person loses faith in his own works and gives himself as a condemned sinner to the grace of God he becomes clothed in the righteousness of the Son…Instead of his own works put forth in an effort to gain merit, he claims the word of Jesus, “This is the work of God, that you believe in him whom he has sent’ (John 6:29).”
From C. O. Rosenius, Romans: A Devotional Commentary (Minneapolis, MN: Ambassador Publications, 1978), pp. 38-39.