Chapter four serves two purposes in Paul’s explanation of salvation as God’s gift of righteousness that comes only through faith. First, by quoting from two passages from the Hebrew Scriptures, he ensured that his Jewish readers could not escape the knowledge that this truth had in their grasp the whole time. Second, by using two different examples from two different points in Jewish history, he solidified the inevitable conclusion that salvation has always come through faith alone, apart from the law of which they were so proud.
In Romans 4:1-5 Paul invoked the father of the Jewish nation, Abraham, and quoted what seems to have been his favorite go-to verse and example on this topic, Genesis 15:6 (see also Galatians 3:6): “Abraham believed God, and it was credited to him as righteousness.” What better proof is required than that Abraham’s righteous standing with God came through faith alone?
Yet Paul foresaw that some may object because the law had not yet been given. Of course righteousness could come through faith before the law, but what about after the law? Paul gladly answered, this time using David as his example, a man who desperately loved God’s law, as evidenced in the Psalms (Romans 4:6-8). However, even David sang of the blessedness of God’s forgiveness which comes “apart from works.” Fine, they might continue, but David was certainly circumcised, the visible sign of God’s covenant law. True, Paul responded, but Abraham’s faith came even before his circumcision (Romans 4:9-12). In short, Abraham had nothing but his faith, and even David celebrated that gift was still true in his day.
Throughout the remainder of the chapter, Paul continued to dismantle the arguments that God’s righteousness could be related to law in any way (Romans 4:13-22). Even the promises that God made to Abraham were given before his circumcision; only his faith was required to activate them. In fact, Paul argued, if righteousness came through obeying God’s law, how could anyone ever be sure they were obedient enough? And since everyone is guilty of sin, how much good could make up for our sin? “For this reason it is by faith so that it may be by grace with the result that the promise may be certain” to everyone who believes, both Jews and Gentiles.
Although many will debate what faith is and what exactly a person must believe in order to be saved and obtain God’s gift of righteousness, Romans 4:21 reveals the simple truth: Abraham “was fully convinced that what God promised he was also able to do.” For the past 2,000 years “what God promised” is solely based in the death and resurrection of Jesus (Romans 4:23-25).