By Clement Harrold

September 18, 2025

You don’t have to read the Bible for very long before you arrive at the figure of Abraham. Most of us know the story: God calls Abraham to become the father of a great nation, and soon after He established circumcision as the sign of His covenant with Abraham and his descendants (see Gen 17). For modern readers, this decision can seem archaic and downright weird. Why did God require circumcision for so many centuries? What did it accomplish, exactly? Wouldn’t a less violent ritual have been more appropriate? We’ll explore these questions below.

An Occasion for Grace

Catholic theologians have typically regarded circumcision as an Old Covenant sacrament. Unlike the New Covenant sacraments, circumcision didn’t impart grace ex opere operato; that is, it didn’t impart grace automatically simply on account of the action being performed. But it did serve as both a sign of, and the occasion for, the saving grace of God. Indeed, circumcision was a preparation for baptism, and its effects were similar.

According to thinkers like St. Augustine and St. Thomas Aquinas, when the circumcision of a baby boy was accompanied by an act of faith on the part of the parents—specifically, an act of faith in the coming Messiah (i.e. Christ)—then the baby would be cleansed of the stain of original sin. In this respect Augustine and Aquinas build on St. Paul, who points out that circumcision apart from faith was useless:

Is this blessing pronounced only upon the circumcised, or also upon the uncircumcised? We say that faith was reckoned to Abraham as righteousness. How then was it reckoned to him? Was it before or after he had been circumcised? It was not after, but before he was circumcised. He received circumcision as a sign or seal of the righteousness which he had by faith while he was still uncircumcised. The purpose was to make him the father of all who believe without being circumcised and who thus have righteousness reckoned to them. (Rom 4:9-11; cf. 2:25)

This points to a crucial difference between circumcision and baptism. A validly performed baptism is efficacious regardless of the faith of the parents. This is not the case with circumcision. In addition, Aquinas notes that the debt of temporal punishment for sin which is removed in baptism is not removed in circumcision, or at least not to the same degree (see ST III.70.4.ad5). Likewise, actual grace is more copiously bestowed in baptism than in circumcision.

More generally, it’s important for us to see the ways in which circumcision was always intended as a preparation for baptism. Aquinas suggests that circumcision was carried out on the eighth day after birth in order to prefigure the spiritual circumcision which Jesus would bring about on the eighth day. The Catechism of the Catholic Church explains this language of “eighth day:”

By a tradition handed down from the apostles which took its origin from the very day of Christ’s Resurrection, the Church celebrates the Paschal mystery every seventh day, which day is appropriately called the Lord’s Day or Sunday. The day of Christ’s Resurrection is both the first day of the week, the memorial of the first day of creation, and the “eighth day,” on which Christ after his “rest” on the great Sabbath inaugurates the “day that the Lord has made,” the “day that knows no evening.” (#1166)

Already in the Old Testament we find prophecies of the spiritual circumcision which Christ will enact in the hearts of His people through the eighth and eternal day which follows His Passion and Resurrection (see Deut 30:6; 10;16; cf. Acts 2:37; Rom 2:29; Col 2:11). Finally, it’s worth noting that for Aquinas even the graces attached to circumcision were the fruit of Christ’s Passion; circumcision served as an occasion for grace only insofar as it was as a sign which pointed forward to, and drew its power from, Christ’s saving work on the Cross.

Why God Chose Circumcision

Now that we’ve considered what circumcision accomplished, we’re in a better position to ask why God chose it. On its face, the severing of the foreskin seems like a strange ritual for an omnipotent deity to choose as the sign of His covenant with His people. In reflecting on this topic, Aquinas describes circumcision as “a profession of faith and a remedy against carnal concupiscence” (ST III.70.2.ad1). He goes on to offer three reasons for why circumcision was a fitting covenantal sign:

First, because it was a sign of that faith whereby Abraham believed that Christ would be born of his seed. Secondly, because it was to be a remedy against original sin, which is contracted through the act of generation. Thirdly, because it was ordained as a remedy for carnal concupiscence, which thrives principally in those members, by reason of the abundance of venereal pleasure. (ST III.70.3.ad1)

We can unpack Aquinas’s analysis as follows. First, circumcision was intended to symbolize the faith which the people of Israel had in the coming Christ, who would be born of the seed of Abraham. The fact that every Israelite boy received a mark on his reproductive organ highlighted the truth that his nation had received a special vocation to pave the way for the birth of the Messiah.

Secondly, the act of circumcision (accompanied by sincere faith) removed the stain of original sin, which is passed down from father to child through sexual reproduction. Circumcision was therefore a fitting ritual for underscoring the gravity of original sin, as well as an appropriate remedy for the kind of sin which is passed down from generation to generation through the act of procreation.

Third, circumcision was given to help God’s people overcome the disordered affections of their lower appetites and arrive at true spiritual maturity and freedom. Since in every age sexual sin is at the forefront of men’s struggle with “carnal concupiscence,” it was fitting for the Israelite males’ sexual organs to be set apart in some tangible way through the act of circumcision. The mark they bore in their flesh was a reminder that they were called to be a radically holy people set apart from the evils of the world around them.

Finally, we might add to Aquinas’s analysis the fact that circumcision carries potential health benefits, particularly in the developing world where bodily hygiene is more difficult. This medical reality undercuts critics of the Bible who depict circumcision as nothing but a bizarre or even barbaric ritual. Circumcision is categorically different from something like female genital mutilation, both because it involves the cutting off of a part of the male body (the foreskin) which God created to be disposable, and because it has the potential to reduce certain health risks, particularly in places like ancient Israel which lacked modern healthcare and sanitation.

What About the Baby Girls?

If circumcision was the Old Covenant sacrament for removing original sin, then what were the women of Israel supposed to do? The traditional answer to this question is that while the baby boys of Israel were cleansed from original sin by the ritual of circumcision accompanied by an act of faith on the part of their parents, the baby girls of Israel were cleansed by the act of faith alone.

One way to think about this is that baby boys and girls were saved by being incorporated into God’s family through the people of Israel. In the case of boys, this incorporation happened through the faith of the parents on the occasion of the boy’s circumcision eight days after birth. In the case of girls, it happened simply through the faith of the parents, perhaps on the occasion of the girl’s naming which usually took place a few days after birth.

Why exactly God placed a more severe (and bloody) demand on the boys of ancient Israel is a matter for theological speculation. But it does seem connected to the way in which men are called to serve as the spiritual heads (and therefore servants) of their respective families. Since the men of Israel had a distinctive role to play in passing the faith of Abraham down the generations until the coming of the Messiah, this distinctive role was formalized in their very flesh. In this way, the sacrificial act of circumcision served as a physical symbol for the life of self-sacrifice which they were called to live out on behalf of their families and their God.

Further Reading

Lawrence Feingold, Touched by Christ: The Sacramental Economy (Emmaus Academic, 2021)

About Clement Harrold

Clement Harrold earned his master’s degree in theology from the University of Notre Dame in 2024, and his bachelor’s from Franciscan University of Steubenville in 2021. His writings have appeared in First Things, Church Life Journal, Crisis Magazine, and the Washington Examiner.