In Genesis 15 God promised Abraham that He would give him many descendants. Abraham had everything. But he did not have a son. He had cattle, he had sheep, and he had tents. But he did not have a son. However, Abraham believed God. He believed that God would give him a son. He merely believed God. He did not do any work. In chapter twenty-two, after God had given him a son, He said to Abraham, "Take now thy son, thine only son Isaac, whom thou lovest, and get thee into the land of Moriah; and offer him there for a burnt offering upon one of the mountains which I will tell thee of" (v. 2). Then Abraham got up early in the morning and took his son to Mount Moriah. He laid the wood for the burnt offering on his son Isaac's back, and Isaac bore the wood for the burnt offering, in the same way that the Lord Jesus bore the cross. When they reached the mountain, Abraham built an altar, laid his son on the altar, and was about to kill him. This is the incident that James recounts when he refers to Abraham's justification. In Genesis 15 God's justification of Abraham was related to his son. And in Genesis 22 God's justification of him was also related to his son.

In Genesis 15 Abraham had no son. But he believed in his heart that if God said He would give him a son, he would surely have a son. In chapter twenty-two he did have a son, but God wanted him to offer up this son. If Abraham had not had faith, he would have said, "God, You told me that You would give me many descendants. Now if I kill my son, will I not lose them all? It is not that I am unwilling to do this; I just want to see Your promise fulfilled. It is not that I dare not do it; I just want to preserve Your faithfulness." Do you think that Abraham's offering of Isaac was a work or an act of faith? What good work is it to kill one's son? What is there to praise about in killing one's own son? That Abraham raised the knife to offer up his son shows that he still believed the promise of chapter fifteen. God had promised to give him many descendants, and to this end He had given him one son. Now if God wanted him to kill this son, it must be that God would raise him up from the dead. This is what Abraham had in mind when he was about to kill his son. His willingness to kill his son shows that he believed that Isaac would be raised from the dead. The faith in Genesis 15 is a faith in Him who calls things not being into being, while the faith in Genesis 22 is a faith in Him who raises people from the dead (Rom. 4:17). In both instances, what Abraham did was not something of work, but of faith. Abraham's act proved that he had faith. This does not mean that Abraham could be justified by killing his son. It means that in pulling out his knife, he proved that he had faith. The proof of Abraham's faith lies in his willingness to offer up his son.

Hence, James did not say that one cannot be justified by faith. Paul says strongly that justification is not by works, but James could not strongly say that justification is not by faith. If the two contradict each other, we would expect one to say, "Justification is of faith, not of works," and the other to say, "Justification is of works, not of faith." But James does not say this. We must not say what James has not said. James does not say that we should not have faith; he says that one should prove his faith with his work. Paul is the one who talks about the principle, so he can boldly declare that justification is of faith and not of works. James is a man of practice. Thus, he says that one must not have faith only, but should have works as well. Only when there are works can a man prove that his faith is genuine. Let us read James 2:21 again: "Was not Abraham our father justified by works in that he offered up Isaac his son upon the altar?" His offering up of his son was a work, and it was this work that proved that he had faith.