Why did Jesus get baptised?

Matthew 3

Don’t think to yourselves, ‘We have Abraham for our father,’ for I tell you that God is able to raise up children to Abraham from these stones.

I indeed baptize you in water for repentance, but he who comes after me is mightier than I, whose shoes I am not worthy to carry. He will baptize you in the Holy Spirit.

Then Jesus came from Galilee to the Jordan to John, to be baptized by him. But John would have hindered him, saying, “I need to be baptized by you, and you come to me?” But Jesus, answering, said to him, “Allow it now, for this is the fitting way for us to fulfill all righteousness.” Then he allowed him.

Matthew 3:9‭, ‬11‭, ‬13‭-‬15

Why did Jesus get baptised? After all, John had pointed out that his baptism was for repentance, and Jesus had never sinned, so he didn't need to repent.

But Jesus said, “Allow it now, for this is the fitting way for us to fulfill all righteousness.”

What does that mean?

I think this might be part of it:

John was making clear that being part of the _physical_ people of God (Israel)was not the same as being saved as part of the spiritual people of God, and that God could raise up people who were not descended physically from Abraham to be part of His saved people (verse 9).

Jesus gave the reason "this is the fitting way to fulfil all righteousness." Thus He could be doing this to show everyone that this was the way to go about being part of this salvation community.

Here is a more detailed explanation from John Piper.

Here's is another explanation from Jonathan Pennington.