Chapter 13.
Of the longing with which the old patriarchs desired to see the revelation of that mystery.
This mystery then, which was manifested in the flesh and appeared in the world, and was preached to the Gentiles, many of the saints of old longed to see in the flesh, as they foresaw it in the spirit. For “Verily,” says the Lord, “I say unto you that many prophets and righteous men have desired to see the things which you see, and have not seen them; and to hear the things which you hear and have not heard them.” And so the prophet Isaiah says: “O that You, Lord, would rend the heavens and come down,” and David too: “O Lord, bow the heavens and come down.” Moses also says: “Show me Yourself that I may see You plainly.” No one ever approached nearer to God speaking out of the clouds, and to the very presence of His glory than Moses who received the law. And if no one ever saw more closely into God than he did, why did he ask for a still clearer vision, saying, “Show me Yourself that I may see You plainly”? Simply because he prayed that this might happen which the apostle tells us in almost the same words actually did happen; viz., that the Lord might be openly manifested in the flesh, might openly appear to the world, openly be received up in glory; and that at last the saints might with their very bodily eyes see all those things which with spiritual sight they had foreseen.
Source: On the Incarnation of the Lord (Against Nestorius) (New Advent)