If church history teaches us anything, it is that legalism — the belief that we must add something to grace to make us acceptable in God’s sight — perpetually threatens the church. The medieval church, for example, made the system of penance a precondition of divine forgiveness. More recently, some traditions identify true Christians as those who do not drink, dance, or smoke.
The first legalists in church history were the Judaizers described in the New Testament. These false teachers asserted that Gentile converts must believe in Jesus and do works of the Law, such as circumcision, to be declared righteous before God (Acts 15:1–35; Gal. 5:2–6). Even the Philippian church needed to be warned about the Judaizers, and we find this warning in today’s passage.
Using the word dogs, Paul ironically contrasts the Judaizers’ false gospel with the true Apostolic gospel (Phil. 3:2). The ancient Jews did not keep dogs as pets because the dogs living in ancient Israel were wild, unclean scavengers. In turn, the Jews often applied the word dogs pejoratively to Gentiles, for they regarded non-Jews as unclean. In calling members of the Judaizing party “dogs,” Paul warns the Philippians that these Judaizers are actually filthy, even if said Judaizers believe they are cleansing Gentile converts by way of circumcision.
Paul continues, calling the Judaizers “evildoers . . . those who mutilate the flesh” (Phil. 3:2). God instituted circumcision as an old covenant sacrament (Gen. 17:1–14), but its new covenant fulfillment is baptism (Col. 2:11–12). By imposing circumcision on Gentile converts, the Judaizers turned back the clock, returning to the old covenant era of shadows and denying the sufficiency of the cross. The significance of Philippians 3:2 is also seen in that old covenant priests who mutilated themselves became unfit for service (Lev. 21:1–5). Under the new covenant, requiring the circumcision of Gentile believers is akin to mutilating God’s priestly nation (1 Peter 2:5); so the Judaizers, despite their intent, really promoted uncleanness.
True circumcision is heart circumcision, the baptism into (union with) Jesus by faith (Rom. 6:3–4; Col. 2:11). This sets us apart as holy, which is why all who trust in Christ alone are “the circumcision,” the true worshippers of God (Phil. 3:3).