James points out that Abraham’s authentic faith led to divine approval and he cites two Old Testament verses as evidence. The first is from the book of Genesis, but from an occasion before he offered up Isaac, when the Lord made a covenant with him (Gen. 15:6). On that occasion the Lord had declared that Abraham was reckoned as righteous because he believed what God had said.
When James applies that verse to what happened many years later with Abraham on Mount Moriah, he is saying that Abraham’s faith was active all along the path that Abraham took to and up Mount Moriah, and that his readiness to offer up his son proved or completed the genuineness of his faith. This action by him on Moriah fulfilled that previous justification in that it proved his justification was true.
This only means that every activity motivated by faith completes it and reveals that the believer has true faith and is a person who has been justified previously by God. Believers have to act in faith all the time. Abraham did nothing on that occasion apart from faith in God. His activity on this occasion showed that the faith he had commenced years before was genuine.
The second reference may be to 2 Chronicles 20:7 where Jehoshaphat says that Abraham was God’s friend or to Isaiah 41:8 where God says that Abraham was his friend. This was a great privilege for Abraham. Maybe some might have wondered if the request made by God to Abraham was an indication that God did not like him and was trying to destroy his promises. Whether anyone thought so or not, James reminded his readers that the Lord regarded Abraham highly and told a later generations of Israelites that Abraham had been his friend. Is James saying that faith in God and friendship with God go together?
There is a sense in which Rahab’s faith is more surprising because, unlike Abraham, she had no personal direction from God on which to base her actions. Instead, she had had to exercise a brave faith, which included the awareness that she deserved to be condemned with the rest of Jericho. Moreover, we can say that she even had a big faith because she accepted the possibility that others in her family circle would follow her example and reap the benefits. From one point of view, her faith was evangelistic and compassionate.
What blessings did Rahab receive from exercising faith in God at that time? Here are four. First, she married a prominent member of the tribe of Judah called Salmon and they had a godly family – Boaz was her son (Matt. 1:4-5). Second, her descendants became the royal line from which David and other kings of Judah came. Third, she along with Abraham before her became ancestors of Jesus. Fourth, Rahab went to heaven when she died.