12 And he that is eight days old shall be circumcised among you, every man child in your generations, he that is born in the house, or bought with money of any stranger, which is not of thy seed.
(Chapter 17—Verse 3 and following) And the Lord spoke to him, saying: Behold, my covenant is with you, and you shall be the father of a multitude of nations, and your name shall no longer be called Abram, but your name shall be Abraham, for I have made you the father of many nations. It should be noted that wherever we read Testament in Greek, in the Hebrew language it is the word covenant or pact, that is, Berith (). The Hebrews say that God, from his name, which is the Tetragrammaton among them, added the letter He to Abraham and Sarah: for he was first called Abram (), which means lofty father, and later he was called Abraham (), which means father of many: for what follows nations is not part of the name, but is understood. It is not surprising, therefore, that when it seems that the letter Α has been added among the Greeks and us: we have called it the Hebrew letter He added; for the language of that tongue is to write with He (ה), but to read with A (א): just as, on the contrary, the letter A is often pronounced as He.
Verse 7. "And the overseer of the eunuchs imposed names upon them, calling Daniel Belteshazzar (Balthasar), and Hananiah Shadrach, and Mishael Meshach, and Azariah Abednego." It was not only the overseer or master of the eunuchs (as others have rendered it, the "chief-eunuch") who changed the names of saints, but also Pharaoh called Joseph in Egypt Somtonphanec (Genesis 41:45), for neither of them wished them to have Jewish names in the land of captivity. Wherefore the prophet says in the Psalm: "How shall we sing the Lord's song in a strange land?" (Psalm 137:4). Furthermore the Lord Himself changes names benignly, and on the basis of events imposes names of special significance, so as to call Abram Abraham (Genesis 17:5), and Sarai Sarah (Genesis 17:15). Also in the Gospel, the former Simon received the name of Peter (Mark 3:16), and the sons of Zebedee are called "sons of thunder" (Mark 3:17) - which is not boanerges, as most people suppose, but is more correctly read benereem.
And because he is called to what is perfect, Abraham receives the oracle that summons to perfection. “Circumcise,” it says, “every male of yours and circumcise your flesh”; but perfect circumcision is the spiritual one. Indeed, Scripture also teaches this when it says, “Circumcise the hardness of your heart.” Even here many interpret the text to be saying, “Circumcise every male of yours,” that is, your minds; for nothing is more virile than the mind. Moreover, because the male is also holy, it is said, “Every male opening the womb shall be called holy for the Lord.” But what is holier than the mind that produces the seeds of good thoughts by which it opens the womb of the soul, which was closed by the sterility that prevented it from childbearing, so that it might give birth to invisible generations, obviously through that spiritual womb of which Isaiah said, “We have conceived in the womb and given birth to the spirit of salvation”? So what is mandated is the intelligible circumcision of the heart as well as the sensible circumcision of the flesh: the former in truth, the latter in sign. Circumcision then is twofold because it requires the mortification of the mind and the body. The Egyptians in fact circumcise their males in the fourteenth year, and it is said that their women too are circumcised in the same year, because in that year the passion of virility begins to flare up and the menstrual cycles of women commence. But the promulgator of the eternal law requires the mark of carnal circumcision only in males, because in the sexual relationship the man is more impetuous than the woman, and for this reason he wished to check his passionate impulse by the mark of circumcision. Or, because men regard their error as licit, so long as they avoid adultery, and are convinced that the practice of prostitution is in conformity to the natural law, while the truth is that neither men nor woman are permitted to have sexual relationships outside of marriage. But according to a deeper interpretation, the intention is to explain that if the mind has once been purified and circumcised, freed from illicit desires and thoughts, it binds the soul to its own chastity, and, having infused it with purity of the senses, makes it capable of generating good offspring.The law orders that the baby boy be circumcised on the eighth day: evidently a precept that harbors a mystery, because this is precisely the day of the resurrection. Indeed, the Lord Jesus rose from the dead on Sunday. For this reason, if the day of resurrection finds us circumcised and free from excesses and crimes, purified from every filth, cleansed from bodily vices, if you go forth from this day clean, you will rise clean.
A child of eight days shall be circumcised among you. For on the eighth day, that is, after the Sabbath, the Lord rose from the dead, in whose passion and resurrection we are baptized, absolved from the oldness of faults, as if we are renewed by spiritual circumcision; the Apostle explaining and saying: For as many of us as were baptized into Christ Jesus were baptized into His death, therefore we were buried with Him through baptism into death: so that just as Christ was raised from the dead by the glory of the Father, so we also should walk in newness of life (Rom. VI, 3). This number can most fittingly correspond to the time of our resurrection, when we shall be clothed universally with the immortality of the flesh, which we laid down through death, and we shall suffer nothing of sin nor of corruption in the flesh. For our resurrection is also not incongruously figured by the number of the eighth day; because after the six ages of this world and the seventh of rest, that is, the rest of souls, which is now celebrated in another life, the future one will be. Therefore infants were commanded to be circumcised on the eighth day as a sign of the divine covenant to indicate mystically that all the elect by the grace of God would be absolved from all iniquities in this number, cleansed from all corruption of the flesh, and also freed from the very death that they incurred through the guilt of the first transgression.
Every male among your generations, whether born in the house or bought with money, and whoever is not of your seed, shall be circumcised. This signifies that the grace of regeneration and immortality pertains to all the faithful, whether they derive their origin from the stock of Abraham or from another source of the flesh.
[AD 420] Jerome on Genesis 17:3-14