Baptism reveals identity. It manifests to whom I belong (Jesus!) and rejoices in what he did and does in my life. I proclaim I have died to sin and live to walk in newness of life, to bear fruit for God (Romans 7:4, NASB).
Paul talks about the spiritual reality in Romans 6. The chapter’s initial verses follow below.
What shall we say then? Are we to continue in sin so that grace may increase?
May it never be! How shall we who died to sin still live in it?
Or do you not know that all of us who have been baptized into Christ Jesus have been baptized into his death?
Therefore we have been buried with him through baptism into death, so that as Christ was raised from the dead through the glory of the Father, so we too might walk in newness of life.
Immersion in water—baptism—reflects the inward reality. The water symbolizes being cleansed from sin while immersion in it declares I belong to God and live for him.