John Calvin Commentary Romans 4:18

"Who in hope believed against hope, to the end that he might become a father of many nations, according to that which had been spoken, So shall thy seed be." — Romans 4:18 (ASV)

Who against hope, and so on. If we read it this way, the meaning is that when there was no probable reason, indeed, when all things were against him, he still continued to believe. And, undoubtedly, there is nothing more harmful to faith than to fix our minds on what our eyes perceive, so that we seek a reason for our hope from what we see.

We may also read it as “above hope,” and perhaps more appropriately; as if he had said that by his faith he far surpassed all that he could conceive. For unless faith flies upward on heavenly wings, so as to look down on all the perceptions of the flesh as things far below, it will stick fast in the mud of the world.

But Paul uses the word hope twice in this verse. In the first instance, he means a probable basis for hoping, such as can be derived from nature and carnal reason. In the second, he refers to the hope that comes from faith given by God. For when he had no natural ground for hoping, he nevertheless, in hope, relied on the promise of God; and he considered it a sufficient reason for hoping that the Lord had promised, however unbelievable the thing was in itself.

According to what had been said, and so on. This is how I have preferred to render it, so that it may be applied to the time of Abraham. For Paul meant to say that Abraham, when many temptations were drawing him to despair, turned his thoughts to what had been promised to him, so that he might not fail: Thy seed shall equal the stars of heaven and the sands of the sea; but he resignedly adduced this quotation incompletely, in order to stimulate us to read the Scriptures. The Apostles, indeed, at all times, in quoting the Scriptures, took scrupulous care to rouse us to a more diligent reading of them.