4. There is one body and one Spirit, just as also you were called in one hope of your calling;
5. one Lord, one faith, one baptism,
6. one God and Father of all who is over all and through all and in all.
11. As for me, I baptize you with water for repentance, but He who is coming after me is mightier than I, and I am not fit to remove His sandals; He will baptize you with the Holy Spirit and fire.
The baptisme is spiritual = when you let yourself being absorbeb by the holly spirit (it's a rebirth in the faith - you remain imperfect but you feel way better spiritually - you just listen to the holly spirit - when it tells to your heart HEY HO you are going to far on this well you stop / or please this one or this one need your help - you help ... and if needed he'll give you the strenght / faculty to do it). Nobody but Christ can baptise you ... Christians (those who feel like christ = those who feel for others) in being nice (as much as they can - but they can not everything everybody have their own strenght) gives you the envy to have faith like them, they are the premice which help you to get baptised (the begining of the rebirth) in being absorbed by the holly spirit.
Only my point of view of course ...