And he that is eight days old shall be circumcised among you, every male child in your generations, he that is born in the house, or bought with money of any foreigner, who is not of your descendants.
All Commentaries on Genesis 17:12 Go To Genesis 17
Ambrose of Milan
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. .