A person is not a Jew who is one only outwardly, nor is circumcision merely outward and physical. No, a person is a Jew who is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a person’s praise is not from other people, but from God.Romans 2:28-29 NIV
In this passage, Paul expressed that Jewishness is not just a matter of who your parents are or the outward rituals that you participate in. Circumcision was an outward sign of being a Jew, as were Sabbath observance and other Jewish practices. But being a real Jew was more than these external symbols and activities. Being Jewish was a matter of the heart. It is what is on the inside that counts, not the outside appearances.
And I believe that is just as true for those who call themselves Christian. Just being baptized does not make you a Christian. Or participating in the activities of a church. Nor even identifying as a Christian. All those outward things you might do are worthless if there is no change on the inside.
Being a real Christian is a matter of the heart. It is the surrender of self to the Lordship of Jesus, becoming his disciple, and following him wherever he leads. That inward commitment will be reflected in our outward lives. But if your heart is not transformed, then no amount of external activity will matter. Don’t be content with going through the outward motions of being a Christian. Instead, surrender to him as Lord and experience the new life he gives.