"That he might sanctify and cleanse it with the washing of water BY THE WORD." (Eph 5:26) The water is the word of God. Only God's word and his Holy Spirit have the power to give us a new birth, but physical water itself is powerless. Baptism merely symbolizes that we have died (buried) to our old way of life, and live (raised up) to a new life governed by the Spirit and not the flesh, but it symbolizes something that has already occurred; it isn't the water that will make us new inside.