The topic of circumcision in the Bible is probably not one that usually occupies our attention, and yet it is a surprisingly central biblical theme. It occurs in many of the controversies in the New Testament and it is the sign which marks out the community of God’s people in the Old Testament. Moreover, the metaphor of “circumcision of the heart” is one of the key ideas in the Old Testament, appearing in some very significant places like Deuteronomy 30 and Leviticus 26.

But the meaning of circumcision is also somewhat unclear. Bafflingly, when circumcision appears in the New Testament it is often in the context of debates about justification, which people usually think of as a judicial or legal category—God declares us righteous. Yet when circumcision turns up in the Old Testament it is often in the context of something like circumcision of the heart, which people tend to think of as a transformational category—our hearts need to be changed so that we love God. But those are quite different ideas.

So what does circumcision mean? It is impossible to untangle here all the riddles that surround circumcision, instead, I hope briefly sketch out some of the key ideas.

Be Blameless: God’s Requirement

The sign of circumcision first appears in Genesis 17. There God appears to Abraham and calls him to “walk before me and be blameless” (17:2). If Abraham does that, God will “give” him the things which he has promised. In other words, there is a kind of requirement for Abraham to meet for God to deliver on his promises. That condition is “blamelessness” or “perfection” (tāmîm). A quick look through the rest of the Bible shows what that means. For instance, God’s work is “perfect” (Deut 32:4); his way is “perfect” (2 Sam 22:31; Ps 18:30); his law is “perfect” (Ps 19:7); he is “perfect in knowledge” (Job 37:16); and he shows himself “blameless” (2 Sam 22:26; Ps 18:25). In Psalm 15, David asks, “O Lord, who shall sojourn in your tent? Who shall dwell on your holy hill? He who walks blamelessly and does what is right and speaks truth in his heart….” (Ps 15:1–2 ESV). In other words, “blamelessness” represents the very perfections of God himself.

That kind of lofty goal is mirrored in the New Testament. Paul says that we have been chosen in Christ “that we should be holy and blameless before him” (Eph 1:4). Or that Jesus will “present the church to himself in splendour, without spot or wrinkle or any such thing, that she might be holy and without blemish” (Eph 5:27; see also Col 1:22; Jude 24). The idea of Jesus presenting us as “blameless” before the Father at the last day pushes us again toward understanding that blamelessness is the moral perfection that we require in order to live in the presence of a holy and perfect God.

Blamelessness Through Sacrifice

But how could Abraham ever achieve that? Surely that is an impossible goal? The life of Abraham clearly shows he was far from perfect. Yet a closer look at the way the language of “blamelessness” is used in the Old Testament begins to shed light on how God would make the impossible possible.

It turns out that the word “blameless” is used mostly in connection with the sacrificial system and with the requirement that people offer a “blameless” or “spotless” animal in their place to atone for their sins (e.g. Lev 1:3; 3:1). Hence, for those schooled in the daily practices of the sacrificial system, when they read Genesis 17 they would have immediately recognized that although God was calling them to “blamelessness,” God had also provided for the fact that they were not blameless. He had provided a means of atonement and forgiveness for their flawed lives.

Again, the New Testament confirms that idea. In the New Testament Jesus is described as the ultimate “blameless” sacrifice. So Peter says, “you were ransomed from the futile ways inherited from your forefathers, not with perishable things such as silver or gold, but with the precious blood of Christ, like that of a lamb without blemish or spot” (1 Pet 1:18–19). Similarly, the writer of Hebrews says, “how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God” (Heb 9:14). It is through Jesus’ blameless sacrifice that the way is opened for him to present his people as blameless before God at the last day.

In other words, circumcision was a reminder both of God’s call for people to be blameless before him, but it was also a reminder of God’s provision. In the absence of perfection, God had provided the hope of perfection through the sacrifice of a blameless substitute.

Blamelessness Through the Promised Seed

But what does any of that have to do with circumcision? We have already seen in brief how the blamelessness demanded by circumcision finds its fulfillment in Jesus, but how would that have been clear to anyone in the Old Testament era? That brings us to another important word in Genesis 17: “establish.”

Although the blessings of God’s covenant with Abraham extended to many people, like Ishmael and Sarah, the rest of Abraham’s household and ultimately the nations, the covenant is only established with Abraham and with Isaac and with Isaac’s “seed” after him (Gen 17:19). The same idea is affirmed later in the Old Testament where it is stated that God established the covenant with Abraham, Isaac, and Jacob (e.g. Exod 2:24). There is a kind of line of promise bound up with an individual.

That fits neatly within the storyline of Genesis. In Genesis 3:15, after the fall into sin, God promised that a “seed” of Eve would rise up and crush Satan. The rest of Genesis (and the whole Old Testament!) plays out as a kind of ongoing quest to find that seed. That can be seen in Genesis, not only in the genealogies, which focus our attention on individuals as they trace a line from Eve, through Noah, Abraham, Isaac, Jacob and so on. But it can also be seen in the recurring interest of Genesis of one individual over another: Isaac, not Ishmael, Jacob not Esau, Joseph and not his brothers. At every point, the question is: is this the promised seed?

Circumcision captures that hope in a physical sign. That is why the sign was circumcision and not just a tattoo or a bizarre hairstyle: because it was about the promise of a descendant; hence the sign was attached to the instrument of procreation. That also seems to be why only half the population—the men—received the sign: because the sign was never about delineating who was in and who was out, but about what the promise was. The sign did not mark out individuals for salvation, but a community gathered around God’s promise that through a descendant of Abraham, God would save a people for himself.

Circumcision of the Heart

What, then, does it mean to have a circumcised heart? The short answer is that circumcision of the heart is about the appropriation of that promise by faith. To have a circumcised heart is not to be perfect, but it was to take God at his word when he said that he would send a descendant of Abraham, a Messiah, through whom he would save a people for himself.

That promise, obviously, finds its fulfillment in Jesus. Nowhere is that clearer than in Philippians 3. There Paul warns about people who practice circumcision but who have missed the point: they merely “mutilate the flesh” (Phil 3:2) because they have not understood what circumcision was about. Indeed, Paul says he was one of those people. Remarkably, he uses exactly that language of blamelessness: Paul was “as to righteousness under the law, blameless” (Phil 3:6).

But while he had a kind of ‘blamelessness’ or ‘righteousness based on the law’, it was all rubbish. Why was that? It was because he had failed to see Jesus was the one to whom circumcision had pointed. What matters is not the sign, but the one to whom the sign pointed. Finally, however, Paul had come to see that everything that he possessed and had achieved was rubbish compared “knowing Christ” and “gain[ing] Christ” and being “found in him.” In other words, the true circumcision is those who “worship by the Spirit of God and glory in Christ Jesus and put no confidence in the flesh” (Phil 3:3).

Circumcision without recognizing Jesus as God’s promised Messiah is just a mutilation of the flesh. Circumcision was never about saving people, but about pointing them to Abraham’s promised descendant through whom God would save a people for himself—presenting them blameless through a blameless sacrifice for sins. By faith, many people of the Old Testament era looked forward with anticipation for the coming of that Messiah, and we now look back and recognize that in Jesus, God’s Messiah has come. That, too, is why circumcision is no longer necessary. It is because the promised Messiah, Jesus, has finally arrived.