Genesis 17:12

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.

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.

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,…