They are called back to a remembrance of their conversion. Even in the Old Testament where the outward symbolic rite of circumcision was emphasized, God desired not the outward sign, but the inward circumcision of the heart an inward purification. Paul calls it “made without hands” (Greek acheiropoietos) meaning that the circumcision that he was referring to was spiritual and not physical.
This spiritual circumcision was not of the male organ, but of the whole being. This was a stripping away (Greek apekdysis, here translated removal) of the old sinful nature, much as one would strip away a filthy contaminated garment. The evil nature is not eradicated at this point, but its power is forever broken. Christ was now on the throne, but the flesh tries to usurp the throne. Our physical members are not to be instruments of unrighteousness, but of righteousness to God (Rom. 6:11 – 14).
The idea of the “circumcision of Christ,” is that circumcision which He effects by His death, burial, resurrection, and indwelling presence in those who have received Him by faith. He continues the image in the following verse.
Prayer: Spirit of the Living God, I am so thankful for all that Christ has accomplished on my behalf. I praise Him for His great love, the love that nailed Him to the tree for me. God, I know that my evil nature tries to usurp Your place on the throne on my heart. I am so thankful that You are the One holding me, You will never let me go. May I have a circumcised heart that is the mark of my ownership by You. Amen.
 See Rom. 2:28 – 29; 4:1; Phil. 3:3
 See Deut. 10:16; 30:6; and Jer. 4:4 for examples
 Perschbacher, W. J. (Ed.). (1990). The New Analytical Greek Lexicon. Peabody, Massachusetts, USA: Hendrickson Publishers, Inc. Page 38.
 See 1 John 1:8.