Boyd’s Bible Dictionary:
(cutting around). Cutting off the foreskin. A rite, performed on males on eighth day after birth (Gen. 17; Lev. 12:3; Ex. 12:44; John 7:22). Antagonized by Christianity (Acts 15; 1 Cor. 7:18; Gal. 5:2).
Concise Bible Dictionary:
The rite appointed by God to be a token of the covenant that He made with Abraham and his seed, and also the seal of the righteousness of his faith. Every male in Abraham’s house was to be circumcised, and afterward every male of his seed on the eighth day after birth. It signified the separation of a people from the world to God. During the 40 years in the wilderness this rite was not performed, but on entering God’s land all were circumcised at Gilgal, when the reproach of Egypt was rolled away (Josh. 5:2-9). Circumcision became a synonym for Israel, so that they could be spoken of as “the circumcised,” and the heathen as “the uncircumcised” (Judg. 14:3; Ezek. 31:18; Acts 11:3). Contrary to the design of God, circumcision became a mere formal act, when the covenant itself was disregarded, and God then speaks of Israel as having “uncircumcised hearts.” Stephen charged the Jewish council with being “uncircumcised in heart and ears” (Lev. 26:41; Acts 7:51). In Romans 4 Abraham is shown to be “the father of circumcision,” that is, of all that believe as the truly separated people of God.
Hence circumcision is typical of the putting off the body of the flesh by those who accept the cross as the end of all flesh, because Christ was there cut off as to the flesh, “In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the [sins of the] flesh by the circumcision of Christ” (Col. 2:11); and again, “We are the circumcision which worship God by the Spirit, and rejoice in Christ Jesus, and have no confidence in the flesh” (Phil. 3:3). “Mortify therefore your members which are upon the earth” (Col. 3:5).
From Anstey’s Doctrinal Definitions:
God instituted circumcision as a sign of His covenant relationship with Abraham and his descendants, with a view to their blessing in the land of Canaan (Gen. 17:10-11). The Jews understood this to be an irrevocable pledge of God’s blessing on them (Gen. 15:5; 17:10). Since they were in this relationship with God, they believed that it was impossible for them to be eternally lost, because He would be going back on His Word if they were to end up lost.
However, in Romans 2:25-29, Paul explains that circumcision will not shelter a person from the eternal judgment of his sins any more than trusting in the Law will. He shows that a Jew needed to have more than the outward sign of circumcision in his body to be a real Jew of whom God approved. He says, "He is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh: but he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God." The Jews had "circumcision that is outward in the flesh," but they also needed "circumcision of the heart," which involved having faith, if their eternal destiny was to be secure. Circumcision is an outward sign promising outward blessing to Abraham and his descendants. It was connected with temporal blessings, such as: possession of the land of Canaan, abundant growth of crops, good health, protection from their earthly enemies, etc. These temporal things have to do with life on earth under the favour of God. The Jews, however, were mistakenly trusting in the rite of circumcision, which is connected with temporal blessing, and were imagining that it secured their eternal blessing.
The Jews are not alone in this misunderstanding. Many professing Christians are likewise trusting in outward things and rites such as: baptism, church membership, confirmation vows, etc., but those things will not secure a person’s eternal blessing either. Paul refers to circumcision in three ways in his epistles:
• It stands for the Jews nationally as opposed to the Gentiles who are regarded as the uncircumcision (Rom. 2:26-27; 15:8; Gal. 2:8-9; Eph. 1:11).
• It indicates the actual rite itself—the literal medical procedure performed on the body (Rom. 2:28; Gen. 17:11).
• It represents a life that is separated to God in faith from the activity of the flesh (Rom. 2:29; Phil. 3:3).