The Bible teaches that Baptism is a symbol- an outward expression of an inward decision. In the life of every Christian, it is an important first step of obedience to God which I declare, to others, my faith in Christ. The identity is in Christ's death, burial, & resurrection. 

Romans 6:3-5 says "Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death? We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life. For if we have been united with him in a death like his, we shall certainly be united with him in a resurrection like his."

Baptism not only identifies us with Jesus Christ, but it also identifies us with His local Church and its doctrine.