Baptism is not a Christian invention. Long before John the Baptizer came along, people used water to purify themselves so as not to offend their gods. Jews took up the practice of immersion to prepare themselves to approach God.
However, the worshiper did all those early practices alone. In Jesus time the mikvah was the place of cleansing for Jews. Jerusalem alone had dozens of them. A person would strip, walk into the flowing water (it had to move in and out), duck completely under the water, then walk up a second set of steps to leave the mikvah.
John practiced a form of this baptism, using the river instead of a mikvah. A person who was baptized by John first repented of his sins and pledged to renew his faith in God. One major difference seems to be that John’s baptism was a one-time cleansing, unlike the mikvah which some did as often as twice a day at Qumran.
Note: For Jews, baptism was something only Gentiles had to do to become Jewish. Mikvah cleansing was not considered to be baptism. John had to transform both concepts of his ministry.
Then Jesus changed the whole water-cleansing image. Jesus was familiar with John’s ministry and understood it as announcing the coming of the Messiah. Jesus fulfilled God’s promise by accepting the mantle of Messiah in the baptism. Picture the scene. John standing in the river preaching to a crowd on the banks. Jesus walking into the water, asking for baptism. John saying, no, this is for sinners. Jesus responding that he will accept all our sins. God the Father, in His joy, sent a visual image of the Holy Spirit and announced to Jesus that He was pleased.
Then, Jesus took up the water baptism of John, adding the presence of the Holy Spirit. It is not clear that Jesus personally baptized people. It may have been done by his disciples only. See John 3:22-4:3. Even so, what an experience it must have been.
As a result, Christians have continued the practice much as John and Jesus did it. Some immerse, some sprinkle, some even go to the nearest river. For us, baptism takes two forms. The water represents the ancient idea of cleansing. We confess to we are sinners in the eyes of God and we represent becoming clean with the water. More importantly, we have the presence of the Spirit by the Grace of God.
Most of us do not see the Holy Spirit like a dove, but that does not mean the Spirit is not present. God cares about us and, while He cannot be here in person, His Spirit can be, and is with us.
It would be nice to have the Spirit be a human standing beside each of us whom we could ask for advice. The Spirit could say, “Don’t eat that, and other helpful advice.”
The Spirit is present, but we must work to hear and understand that still, small voice. Constant prayer, study, and conversations with fellow Christians keep us tuned into the Spirit. Remember that Jesus called us to baptize and teach new believers.
He cannot allow the teaching to slide into the background. How else can we know the presence of the Spirit?
Read my earlier comments on this theme here.
Be righteous and do good.