Fred,
Matt 28:19 is not on your side of this argument.
Matt 28:19 lists three things that the Apostles, and through them each teacher of the Gospel today, were supposed to do.
First, they were to Go.
Then they were to Make Disciples (learners).
Then they were to Baptize those Disciples.
These are all things that the Apostles, and we, are to DO.
This is not "Spirit Baptism" because that is not something that we can do.
And when we consider that Mark 16:16 is another writer's (Mark's) rendering of this same event (and that it is also inspired by the Holy Spirit), and that in Mark we are told that belief of the Gospel message and baptism (the thing the Apostles (and we) were commanded to do) leads to salvation, we must come to the conclusion (if we are honest with ourselves and Scripture) that the baptism in Matthew is water baptism that leads to salvation, not something that follows after salvation.