Genesis 22:17

For when God made promise to Abraham, because he could swear by no greater, he sware by himself, Saying, Surely blessing I will bless thee, and multiplying I will multiply thee. [Genesis 22:17] And so, after he had patiently endured, he obtained the promise. For men verily swear by the greater: and an oath for confirmation is to them an end of all strife. Wherein God, willing more abundantly to show unto the heirs of promise the immutability of his counsel, confirmed it by an oath: That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us: Which hope we have as an anchor of the soul, both sure and stedfast, and which entereth into that within the veil; Whither the forerunner is for us entered, even Jesus, made an high priest for ever after the order of Melchisedec.

Let us then cling to his blessing, and let us see what are the ways of blessedness. Let us recall the events of old. Why was our father Abraham blessed? Was it not because he performed justice and truth through faith? Isaac, knowing the future in confidence, was willingly led forth as a sacrifice.

Rightly then is he blessed because he was faithful; and rightly was he faithful because he was patient.

Let us return now to ourselves and treat the moral subject in every detail.The apostle says, as we have already related above, “The first man was of the earth, earthly; the second man from heaven, heavenly. Such as is the earthly, such also are the earthly; and such as is the heavenly, such also are they that are heavenly. As we have borne the image of the earthly, let us bear also the image of the heavenly.” You see what he is showing, that if you remain in that which is first, which is of the earth, you will be rejected, unless you change yourself, unless you have been converted, unless, having been made “heavenly,” you have received “the image of the heavenly.” This is the same thing he also says elsewhere: “Stripping yourselves of the old man with his deeds and putting on the new, who has been created according to God.” He writes that very thing also in another place: “Behold, the old things are passed away, all things are made new.”19
For this reason therefore God renews his promises to show you that you also ought to be renewed. He does not continue in the old, lest you also continue as “the old man”; this is said “from heaven,” that you also might receive “the image of the heavenly.” For what will it profit you if God should renew the promises and you should not be renewed? If he should speak from heaven and you should hear from earth? What does it profit you if God binds himself with an oath and you should pass over these things as if hearing a common story?

What person now needs an explanation to know how the seed of Christ is multiplied who sees the preaching of the gospel extended from the ends of the earth “to the ends of the earth”? And who sees that there is now almost no place which has not received the seed of the Word? For indeed this also was prefigured in the beginnings of the world when God said to Adam, “Increase and multiply.”

The bonds indeed with which they bind us are our passions and vices with which we are bound until “we crucify our flesh with the vices and concupiscences” and so at last “break their bonds asunder and cast away their yoke from us.”47The seed of Abraham, therefore, that is, the seed of the Word, which is the preaching of the gospel and faith in Christ, has occupied “the cities of their enemies.”

To be able to find [these treasures], we need the help of God who alone can “break in pieces the doors of bronze” by which they are shut up and hidden and who “cuts asunder the bars of iron” and the bolts by which access was prohibited for attaining all the truths that were written and hidden in Genesis. [These truths are] concerning the different kinds of souls, concerning the seeds and generations that either pertain directly to Israel or are separated much further from his offspring.

In the former promise there was only the statement; here an oath is interposed, which the holy apostle writing to the Hebrews interprets in this way, saying, “God, meaning to show the heirs of the promise the immutability of his counsel, interposed an oath.” And again, Scripture says, “Men swear by one greater than themselves.” “But God, because he had no one greater by whom he might swear,” “ ‘I swear by myself,’ said the Lord.” It was not that necessity forced God to swear (for who would exact the oath from him?), but as the apostle Paul has interpreted it, that by this he might point out to his worshipers “the immutability of his counsel.” So also elsewhere it is said by the prophet, “The Lord has sworn nor will he repent: You are a priest forever according to the order of Melchizedek.”12At that time in the first promise there is no reason stated why the promise is given, only that he brought him forth and “showed him,” Scripture says, “the stars of heaven, and said, ‘So shall your seed be.’ ” But now he adds the reason on account of which he confirms with an oath the promise which will be steadfast. For he says, “Because you have done this thing and have not spared your son.” He shows therefore that because of the offering or passion of the son the promise is steadfast. This clearly points out that the promise remains steadfast because of the passion of Christ for the people of the Gentiles “who are of the faith of Abraham.”

It is written in the prophet speaking in the person of the Lord, “I have used similitudes by the ministries of the prophets.” What this statement means is this: Although our Lord Jesus Christ is one in his substance and is nothing other than the Son of God, nevertheless he is represented as various and diverse in the figures and images of the Scripture.For example, as I recall we have explained in what precedes that Christ himself was Isaac, in type, when he was offered as a holocaust. Nevertheless the ram also represented him. I say furthermore that he is exhibited also in the angel who spoke to Abraham and says to him, “Lay not your hand on the boy.” For he says to him, “Because you have done this thing, I will certainly bless you.”
He is said to be the sheep or the lamb that is sacrificed in the Passover, and he is designated as the shepherd of the sheep. He is also described, no less, as the high priest who offers the sacrifice.

But what does it profit me, if the seed of Abraham, “which is Christ,” should possess “the cities of his enemies for an inheritance” and should not possess my city? If in my city, that is in my soul, which is “the city of the great king,” neither his laws nor his ordinances should be observed? What does it profit me that he has subjected the whole world and possesses the cities of his enemies if he should not also conquer his enemies in me, if he should not destroy “the law which is in my members fighting against the law of my mind and which leads me captive in the law of sin”?So therefore let each one of us do what is necessary that Christ may also conquer the enemies in his soul and in his body, and, subjecting and triumphing over them, may possess the city even of his soul. For in this way we are made to belong to his portion, the better portion, which is “as the stars of heaven in glory,” that also we might be able to receive the blessing of Abraham through Christ our Lord, “to whom belongs glory and sovereignty forever and ever. Amen.”