The promise to Abraham was staggering in its scope. It was not a promise about a piece of land or a favorable harvest or a long life. "For the promise to Abraham or to his descendants that he would be heir of the world was not through the Law but through the righteousness of faith" (Romans 4:13). Heir of the world. The promise that had begun with a word spoken to one man in Mesopotamia was reaching toward something that had no national border.

Paul now explains why the promise had to come through faith rather than law. "For if those who are of the Law are heirs, faith is made void and the promise is nullified; for the Law brings about wrath, but where there is no law, there also is no violation" (Romans 4:14–15). The law and the promise operate on incompatible grounds. A promise is a gift that depends on the giver's faithfulness. A law is a standard that depends on the recipient's performance. If the inheritance of the promise required law-keeping, then anyone who failed to keep the law perfectly — which is every person — would forfeit it. The promise would be no promise at all. It would simply be a very demanding contract, and the wages of falling short of a contract are not blessings but penalties.

The promise, then, had to be through faith, "so that it would be certain to all the descendants, not only to those who are of the Law, but also to those who are of the faith of Abraham, who is the father of us all" (Romans 4:16). Certainty is the point. A gift that depends entirely on the giver can be depended upon. A wage that depends on the earner's performance is as uncertain as the earner's ability to earn it. God guaranteed the promise by grounding it not in Abraham's performance but in His own character.

What that faith looked like in Abraham is worth pausing at. The God he trusted is described as the one "who gives life to the dead and calls into being that which does not exist" (Romans 4:17). He was not trusting a possibility. He was trusting an impossibility — that a man nearly a hundred years old and a woman whose womb had never produced a child would become the parents of a people as vast as the stars. "Without becoming weak in faith he contemplated his own body, now as good as dead since he was about a hundred years old, and the deadness of Sarah's womb; yet, with respect to the promise of God, he did not waver in unbelief but grew strong in faith, giving glory to God, and being fully assured that what God had promised, He was able also to perform" (Romans 4:19–21).

Paul is not describing a man who closed his eyes to the evidence. Abraham looked at the evidence clearly — his body, Sarah's womb, the full weight of the natural impossibility — and then set it against the word of God and found that the word was the stronger thing. Faith is not the decision to stop thinking. Faith is the decision to trust the only one whose word can be trusted absolutely.

This was credited to Abraham as righteousness — and then Paul makes the application that the whole passage has been building toward. "Now not for his sake only was it written that it was credited to him, but for our sake also, to whom it will be credited, as those who believe in Him who raised Jesus our Lord from the dead, He who was delivered over because of our transgressions, and was raised because of our justification" (Romans 4:23–25).

The crediting of righteousness to Abraham was not a private transaction recorded in a book no one else would read. It was a pattern, laid down in the scriptures, so that every subsequent generation could see how God operates. He credits righteousness to those who trust Him. He justified Abraham by crediting faith. He justifies us by crediting faith — faith in the God who raised Jesus from the dead. Abraham trusted God to give life to what was as good as dead. We trust the God who has actually done it, who raised His Son from a sealed tomb and declared the debt of our transgressions paid.

The faith that justifies is not a bare mental conclusion. It is the kind of faith Abraham had — faith that fixes itself on the word of God and does not waver in the face of everything that argues against it. It is a faith that God recognizes, that He credits, and on the basis of which He declares a person righteous — not because the faith itself is the payment, but because it receives the gift that Christ's death and resurrection purchased.