1 Great indeed was the faith of Abraham. For while in the case of Abel, and of Noah, and of Enoch, there was an opposition of reasonings only, and it was necessary to go beyond human reasonings; in this case it was necessary not only to go beyond human reasonings, but to manifest also something more. For what was of God seemed to be opposed to what was of God; and faith opposed faith, and command promise.
I mean this: He had said, “Get you out of your country, and from your kindred, and I will give you this land.” “He gave him none inheritance in it, no not so much as to set his foot on.” Do you see how what was done was opposed to the promise? Again He said, “In Isaac shall your seed be called”, and he believed: and again He says, Sacrifice to Me this one, who was to fill all the world from his seed. You see the opposition between the commands and the promise? He enjoined things that were in contradiction to the promises, and yet not even so did the righteous man stagger, nor say he had been deceived.
For you indeed, he means, could not say this, that He promised ease and gave tribulation. For in our case, the things which He promised, these also He performs. How so? “In the world” (He says), “you shall have tribulation.” “He that takes not his cross and follows Me, is not worthy of Me.” “He that hates not his life shall not find it.” And, “He that forsakes not all that he has, and follows after Me, is not worthy of Me.” And again, “You shall be brought before rulers and kings for My sake.” And again, “A man's foes shall be they of his own household.” But the things which pertain to rest are yonder.
But with regard to Abraham, it was different. He was enjoined to do what was opposed to the promises; and yet not even so was he troubled, nor did he stagger, nor think he had been deceived. But you endure nothing except what was promised, yet you are troubled.
Source: Homilies on the Epistle to the Hebrews (New Advent)