My own view is that baptism, prior to the Resurrection, was a publicly symbolic act of death and rebirth, When John the Baptist baptized Jesus, the Holy Spirit came down to Him in the form of a dove so that the mortal Jesus would be indwelt and thus began His ministry.
After the Resurrection, the Holy Spirit came down to live inside the many who began speaking in tongues. So salvation and the indwelling of the Holy Spirit comes at the time of confession of sin and asking Christ into our hearts but we are still commanded to be baptized as a public testimony of our private, personal conversion.
I was not baptized until many years after receiving Christ and believe I was saved from the moment of receiving Christ and the Holy Spirit, not when I was baptized.
In addition, what is to become of the person who receives Christ in the desert and dies before he finds water? Tough luck?
That would be a Baptism of the Holy Spirit.