Why is the circumcision of Jesus significant?

The act of circumcision, as described in Luke 2:21, was vital because it marked Jesus' entry into the covenant that required adherence to the law by His people. Since Christ had no need to be made righteous, His circumcision declared His commitment to fulfill the law completely for His elect. This act itself signifies that He became the righteousness of His people, fulfilling all aspects of the law so that they might be justified through Him. Furthermore, His circumcision symbolizes the deeper spiritual reality of the circumcision of the heart that believers experience through the Holy Spirit.