I occasionally hear people argue that Romans 4:17-22 was written to show that Abraham's justification was a process that spanned many years. In other words, Abraham was not justified by a singular act of faith, as might be inferred from Romans 4:3, but was justified as he lived out his faith.
In this short article, I will show that the Apostles Paul and James carefully wrote their letters in a manner that dispels this notion that Abraham was justified over a period of time.
In Romans 4:17-22, Paul is not referring to Abraham's justification-by-faith moment in Genesis 15:6, nor is he referring to Abraham's justification as an ongoing process that spanned from at least Genesis 15:6 (when he was probably between 75 and 85 years old) until he was at least nearly 100 years old. Rather, he is describing a singular moment of faith that occurred in Genesis 17:5 (when he was about 100 years old) that characterized the faith he had when he believed unto justification in Genesis 15:6.
In James 2:21-23, James did something similar, but instead of referring to a moment of bare faith, he gives an example of Abraham's works-empowered faith by which he was justified by works. James is careful to say that he is speaking of two different types of justification. Abraham was justified by faith in Genesis 15:6, but was justified by works in Genesis 22:9-12.
Abraham's experiences in Genesis 17:5 (as described in Romans 4:17-22) and Genesis 22:9-12 (as described in James 2:21-23) did not contribute to or evidence the justification-by-faith moment he had in Genesis 15:6. As mentioned above, Paul uses Abraham's experience in Genesis 17:5 to describe the faith he had in Genesis 15:6. James uses Abraham's experience in Genesis 22:9-12 to show that works-empowered faith (i.e., faith working together with works) can result in justification by works.
Both Paul and James express that they are referring to these experiences as subsequent to Abraham's justification-by-faith moment by referring back to Genesis 15:6 with the qualifying expressions "And therefore" (Romans 4:22) and "And the Scripture was fulfilled" (James 2:23). These two statements prove that Abraham's justification in Genesis 15:6 was not part of a process. It was a singular event. Again, it is important to see how both Paul and James refer back to Genesis 15:6 and speak of his past justification using the Greek aorist tense.