The chapter
Simply John appears in the wilderness of Judea telling people to repent, and crowds come out to be baptised in the Jordan. He warns that someone stronger is coming. Then Jesus arrives to be baptised, John objects, and gives way.
Context Matthew introduces John the way he introduced Jesus, with a prophet and a quotation, and then describes his clothing in a sentence that another book of the Bible has used before.
Verse 3
Simply Matthew says John is the one Isaiah spoke of: a voice crying in the wilderness, make the way of the Lord ready.
Context It is worth opening Isaiah beside this, because the wilderness is in a different place in the sentence. Matthew has the voice crying IN THE WILDERNESS, so the desert is where the man stands. Isaiah has the voice call out and then says prepare the way of the Lord IN THE WILDERNESS, so the desert is where the road is built. Both served editions agree with each other on both halves: Segond too puts the crier in the desert at Matthew and the road in the desert at Isaiah. This is not a difference between translations, it is a difference between the two books, and the reader can see it by opening one after the other.
Verse 4
Simply John wore camel hair with a leather belt round his waist, and ate locusts and wild honey.
Context The belt is a quotation. When messengers describe a prophet to a king in the Second Book of Kings, they say he was a hairy man wearing a leather belt around his waist, and the king answers, that is Elijah. Matthew gives John the same two details in the same order. Malachi ends with a promise that Elijah will be sent before the day of the Lord. Matthew does not say John is Elijah in this chapter; he dresses him and lets the reader who knows the earlier books hear it.
Verses 7-12
Simply To Pharisees and Sadducees arriving for baptism, John says descent from Abraham will not save them, that God could raise children to Abraham out of the stones on the ground, and that the axe is already at the root of the trees.
Context His images are all of separation and all agricultural: the tree that does not bear is cut down, the winnowing fork clears the floor, the wheat goes to the barn and the chaff burns. Verse 11 is the one to read carefully, because the editions do not all say the same thing. In ten of the thirteen editions this app offers, John says the one coming will baptise with the Holy Spirit AND WITH FIRE; in three, the sentence stops at the Holy Spirit. The two French editions disagree with each other: Segond 1910 has et de feu, the Bible Libre does not. Since fire is what the very next verse does to the chaff, the difference is not decorative, and it is one a reader can check in the app by switching edition.
Verses 13-17
Simply Jesus comes from Galilee to be baptised. John tries to stop him, saying he is the one who needs baptising. Jesus tells him to allow it, and John allows it. As he comes up from the water the heavens open, the Spirit descends like a dove, and a voice calls him a beloved Son.
Context John's objection is in the text, not smoothed away: the man baptising for repentance says he is the one who should be in the water. The answer he gets is short and is not an explanation, only that it is fitting for them to fulfil all righteousness. The dove is a comparison and the text keeps it as one, saying the Spirit descended LIKE a dove. The voice speaks about him rather than to the crowd, and the words it uses are the ones Matthew will use again at the transfiguration.