What happened at the baptism of Jesus?
(The relevant text from the Fourth Gospel is below.)
John the Baptist was baptising many people. From John's perspective, it is implied that at each baptism he saw the Spirit descend and then depart. But when John baptised Jesus, the spirit remained.
This presumably means that all who were baptised by John were briefly touched by divinity but Jesus was transformed and became divine.
So, from John's perspective, it would seem that baptising was primarily a means of detecting, and 'making' the Messiah - the Lamb of God.
What about the people who were being baptised - first by John, then by the disciples - but not by Jesus himself; after the Messiah had been discovered? (Referenced later in the Fourth Gospel.) Presumably these baptisms were done in order to have people touched by the Spirit. Perhaps this induced a - temporary - change of heart (repentance) that could be built-upon.
The Gospel of Luke - 3:3 (presumably) quotes someone who remembered that John had been "preaching the baptism of repentance for the remission of
sins". What does this mean, if true?
My guess is that those baptised by John were temporarily cleansed of all sin, were turned towards God - so that they could commune with the divine Spirit. When this happened to Jesus, he realised who he was, became fully divine, began his ministry.
But Jesus did not baptise with water - but 'baptised' with the Holy Ghost. And we know (from later in the Fourth Gospel) that the Holy Ghost came only after Jesus had ascended. This seems to be using 'baptise' metaphorically (as we would term it, although at that time and place such a metaphor was literal as well as symbolic) - it is a reference to what Jesus would ultimately achieve by enabling all Men who 'followed' him to become resurrected, divine, and attain life everlasting.
Thus baptism seems to be a matter of being touched by divinity; either temporarily, or else as a permanent process - to become oneself divine.
In other words (at least when performed by John or the disciples); baptism was a temporary divine transformation; analogous to the permanent divine transformation that is resurrection to eternal life.
Note: By 'transformation' to divine I mean the term literally; since we and Jesus are siblings, and the actual children of God, we have the nature and possibility to become divine in the same way (to a subordinate degree, since we dwell in God's creation) as God the creator. It is therefore a 'process' somewhat resembling the metamorphic transformation of caterpillar to butterfly. It follows that there is more than one god in addition to the creator, including - potentially - as many gods as there are Men. (Although in practice some Men - perhaps most Men - reject the gift of Christ to his followers; that of resurrection to eternal life: to god status.)
John 1:  And this is the record of John, when the Jews sent priests and Levites from Jerusalem to ask him, Who art thou?
 And he confessed, and denied not; but confessed, I am not the Christ.
 And they asked him, What then? Art thou Elias? And he saith, I am not. Art thou that prophet? And he answered, No.
 Then said they unto him, Who art thou? that we may give an answer to them that sent us. What sayest thou of thyself?
 He said, I am the voice of one crying in the wilderness, Make straight the way of the Lord, as said the prophet Esaias.
 And they which were sent were of the Pharisees.
 And they asked him, and said unto him, Why baptizest thou then, if thou be not that Christ, nor Elias, neither that prophet?
 John answered them, saying, I baptize with water: but there standeth one among you, whom ye know not;
 He it is, who coming after me is preferred before me, whose shoe's latchet I am not worthy to unloose.
 These things were done in Bethabara beyond Jordan, where John was baptizing.
 The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.
 This is he of whom I said, After me cometh a man which is preferred before me: for he was before me.
 And I knew him not: but that he should be made manifest to Israel, therefore am I come baptizing with water.
 And John bare record, saying, I saw the Spirit descending from heaven like a dove, and it abode upon him.
 And I knew him not: but he that sent me to baptize with water, the same said unto me, Upon whom thou shalt see the Spirit descending, and remaining on him, the same is he which baptizeth with the Holy Ghost.
 And I saw, and bare record that this is the Son of God.
 Again the next day after John stood, and two of his disciples;
 And looking upon Jesus as he walked, he saith, Behold the Lamb of God!