Circumcision in the Bible made its appearance in Genesis 17, when God appeared to Abraham and made a covenant with him. The sign of this covenant for Abraham and his offspring was that “Every male among you shall be circumcised.” (Genesis 17:10) Male slaves were to be circumcised as well. So every living male was to have his foreskin removed and every male child born to Abraham and his descendants was to be circumcised. Any male who was not circumcised would be cut off (excluded) from his people as a covenant breaker.

Circumcision was practiced by Near Eastern cultures outside of the Israelites. “The circumcision of male boys was a common practice among the Ammonites, the Moabites, the Edomites and the Egyptians. “ (Jeremiah 9:25-26) In these cultures, it was adolescent and adult males who were circumcised, not infants. So it is theorized the ritual was associated with male fertility rites or preparation for marriage. The Philistines were an exception to the rule among the people in Canaan, so they were sometimes referred to as uncircumcised Philistines (Judges 14:3).

Early Greek writers such as Heroditus attributed the origins of circumcision to the Egyptians and Ethiopians: “But as to the Egyptians and Ethiopians themselves, I cannot say which nation learned it from the other; for it is evidently a very ancient custom.”

The practice of circumcision continued under the Mosaic Law. Every male child was to be circumcised (Leviticus 12:3), as was every male sojourner or slave who wanted to participate in the Passover (Exodus 12:43-49). No foreigner, “uncircumcised in heart and flesh,” could enter the sanctuary (Ezekiel 44:9). So circumcision became the final step in New Testament times for a male Gentile converting to the Jewish religion. Paul was accused of attempting to violate this restriction by bringing uncircumcised Gentiles into the temple (Acts 24:6).

Circumcision also became a point of contention in the early days of the church. There was a sect of Christians who argued that Gentiles needed to first convert to Judiaism—they should be circumcised—before they could belong to God’s chosen people. The first Council of Jerusalem decided this wasn’t necessary (Acts 15). Yet Paul was still refuting this expectation in his letter to the Galatians. He said if someone accepted circumcision, they were obligated to keep the whole law (Galatians 5: 3). He even wished that those who continued to unsettle the Galatians over the issue of circumcision, even though it had been settled at the Jerusalem Council, would emasculate themselves (Galatians 5:12).

But circumcision had always been an outward sign of an inward change. There was an expectation from the beginning that there would be heart change in the individual that would be witnessed to by the outward sign of circumcision. Deuteronomy 10:16 calls for the Israelites to circumcise the foreskin of their heart and no longer be stubborn. Commenting on the verse, Samuel Driver said an uncircumcised heart is impervious to good influences and impressions, just as an uncircumcised ear is an ear that cannot listen and takes no pleasure in hearing the word of the Lord (Jeremiah 6:10). Later on in Deuteronomy, as Moses renewed the covenant with Israel, he said: “And the Lord your God will circumcise your heart and the heart of your offspring, so that you will love the Lord your God with all your heart and with all your soul, that you may live.”

Jeremiah called for the men of Judah to circumcise themselves to the Lord by removing the foreskin of their hearts (Jeremiah 4:4). He also warned that judgment would come to all those who were uncircumcised in their hearts (Jeremiah 9:26). In the Lexham Bible Dictionary, Kelly Whitcomb and Getachew Kiros said:

This suggests that a circumcised heart, not just a physical circumcision, is necessary to avoid God’s wrath. Even the circumcised Israelites were considered uncircumcised if they did not have knowledge of Yahweh and practice kindness and righteousness.

In Romans 2, Paul made the same point. The circumcised heart is the true circumcision. If uncircumcised people kept the precepts of the law, they would be regarded as if they were circumcised. Robert Mounce commented: “It is one’s action, not one’s physical features, that count.” Therefore, the person who is physically uncircumcised but keeps the law will condemn the person who is circumcised, but breaks the law (Romans 2:27).

 For no one is a Jew who is merely one outwardly, nor is circumcision outward and physical. But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. His praise is not from man but from God. (Romans 2:28-29)

Notice the inward/outward contrast between what can be seen (physical circumcision and Jewish birth) and what only God can see, the changed heart. As we saw above, Paul’s call for circumcision of the heart by the Spirit, is not new. The true circumcision always was a circumcision of the heart. Douglas Moo, in his commentary The Epistle to the Romans, takes us back to Deuteronomy and Jeremiah:

From the earliest history of Israel, God called on the people to display the kind of inner transformation that could be called a “circumcision of the heart” (e.g., Deut. 10:16; cf. Jer. 4:4). Significantly, it was also recognized that only God could ultimately bring about this heart transformation (Deut. 30:6). There thus grew up in Judaism the expectation that God would one day circumcise the hearts of his people through the work of the Spirit.