For we are the circumcision. We: the apostle of the Gentiles identifies himself with the Gentiles (1 Corinthians 9:2); himself circumcised, he recognizes the great truth that they only are the true circumcision whose hearts are mortified from all worldly and carnal lusts.
Which worship God in the spirit; read, with the best manuscripts, which worship by the Spirit of God. The word λατρεία, worship, is used specially of the Jewish ceremonial service (comp. Romans 9:4; Luke 2:37; Acts 26:7).
We Christians, St. Paul means, have not only the true circumcision, but the only true worship: the temple service prefigured the spiritual worship of the Christian Church. By the Spirit; by his assistance, inspiration: "We know not what we should pray for as we ought: but the Spirit itself maketh intercession for us" (Romans 8:26).
And rejoice in Christ Jesus; rather, glory καυχώμενοι). "He that glorieth, let him glory in the Lord," through whom alone we can obtain salvation, not in any external privileges. And have no confidence in the flesh.
Neither in circumcision nor in any other outward rites.