It is your belief which is not scriptural, but instead a product of rationalism.
Whern is the last time you read your Bible on this? Do you even know what the water baptism is all about? Don't feel bad, most denominsations have gone way, way out of the boundaries on this.
My belief is totally and fully Biblical. For a lengthier accurate treatment, go here:
Baptism of Disciples, or Water Baptism"
Refute this if you can. Until then, I think I'm done here.