Verse 3:24 says:
"...being justified freely by His grace through the redemption that is in Christ Jesus."H. A. Ironside said the following about this wonderful verse:
To be justified is to be declared righteous. It is the sentence of the judge in favor of the prisoner. It is not a state or condition of the soul. We are not justified because we have become righteous in heart and life. God justifies first, then He enables the justified one to walk in practical righteousness. We are justified freely. The word means "without price!" It is the same as in John 15:25, "They hated me without a cause." There was nothing evil in the ways or life of Jesus, for which men should hate Him. They hated Him freely. So there is no good in man for which God should justify him. He is justified freely, without a cause, when he believes in Jesus.
This is "by grace." Grace is not only unmerited favor. Grace is favor against merit. It is the goodness of God, not alone to men who have done, and can do nothing to deserve it, but it is favor shown to men who have deserved the very opposite. "Where sin abounded, grace did much more abound."(H.A. Ironside, Lectures on the Epistle to the Romans, 1928, p. 50.)
What an amazing truth! God has actively chosen to "favor" us against the reality of what we merit or deserve. His love is that great and his grace is that free - "without a cause." We are so privileged to know and serve such a wonderful Savior.