Great questions @Mohembo ! The topic of baptism does seem to come on rather suddenly in this chapter. And you said
I find it difficult not to make connections from one passage of scripture to another. Sorry.
No apologies necessary! It’s such a blessing when we see how the Lord brings revelation and continuity throughout His Word!
On the topic of baptism: It was a practice of the Jews to baptize proselytes as a rite of admission into the Jewish faith in symbol of the proselyte’s cleansing from their former state.
There was also an expectation it would be practiced at the arrival of Messiah because of OT references:
On that day there shall be a fountain opened for the house of David and the inhabitants of Jerusalem, to cleanse them from sin and uncleanness. Zechariah 13:1
I will also sprinkle clean water on you, and you will be clean. I will cleanse you from all your impurities and all your idols. Ezekiel 36:25
The thing that was more unusual was that John was baptizing Jews, whereas Jews usually were baptizing the proselytes.
The prophet, Malachi, communicates the sign of the entrance of Messiah with
See, I am going to send my messenger, and he will clear the way before me. Then the Lord you seek will suddenly come to his temple, the Messenger of the covenant you delight in—see, he is coming,” says the Lord of Armies. Malachi 3:1
Look, I am going to send you the prophet Elijah before the great and terrible day of the Lord comes.
So there was an expectation of an Elijah to prepare the way. And John the Baptist was definitely of the Spirit of Elijah, bold, zealous and defining sin and preaching repentance. It seems like there was (and probably still is) an expectation among Jews of either Elijah himself to return or one like Elijah.
Jesus clears it up for the disciples when they have this exchange in Matthew 17:10-13:
So the disciples asked him, “Why then do the scribes say that Elijah must come first?”
“Elijah is coming and will restore everything,” he replied.“But I tell you: Elijah has already come, and they didn’t recognize him. On the contrary, they did whatever they pleased to him. In the same way the Son of Man is going to suffer at their hands.” Then the disciples understood that he had spoken to them about John the Baptist.
Thank you for bringing in great discussion to the thread!