Scripture-first response
“Baptism is only an outward symbol.”
The water itself has no magic power, but Scripture joins baptism to burial with Christ, calling on His name, remission, and an appeal through resurrection.
What the objection is claiming
The physical element is separated from God’s promise, command, name, and faith.
Colossians 2:12
Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.Open full referenceBaptism is burial and resurrection with Christ through faith in God’s working.
How the passages answer it
Biblical signs can be God-appointed means of covenant response. Baptism is faith in God’s operation, not trust in liquid. Its meaning comes from Christ’s death and resurrection, His name, and His promise.