It’s pretty awesome how Jesus starts his ministry. He settles and kind of puts up shop in Capernaum (which is the hometown of brothers Simon and Andrew, John and James, and Matthew himself) in Galilee.
“The land of Zebulun and the land of Naphtali, the way of the sea, beyond the Jordan, Galilee of the Gentiles,” Matthew 4:15.
Now, Jesus grew up in a town not far from this called Nazareth which was up in the mountains. Jesus didn’t start his ministry in Nazareth though. He spent about thirty years there and worked as a carpenter (more likely a stone mason) under his earthly father, Joseph. Probably around the time Joseph died Jesus went to visit his cousin John, who had been baptizing in the Jordan and preaching repentance.
The Jordan river stems from the Sea of Galilee which is for all practical purposes surrounded by desert. Jesus spends 40 days or more in this desert, and the whole time he is fasting and praying for what is about to happen. This is key, Jesus did not start his ministry without first overcoming temptation through fasting, prayer, and memorization of Scripture. Without this preparation his ministry would not have started at this time.
After completing his time in the desert Jesus returns to Nazareth only to hear that John (the Baptizer) has been arrested. This is when he decides to go to Capernaum, with John incarcerated Jesus must begin and follow up what John had been proclaiming about him with some proof. So he goes out and begins preaching what John had basically been preaching before “Repent, for the kingdom of heaven is at hand,” Matthew 4:17b. He does this to fulfill prophecy, but he starts in the land of the Gentiles! It is like home to him, remember he grew up in Galilee, but to proper Jews this is outsider territory and Matthew makes this quite clear. Jesus, who later says he is called to the Jews, starts his ministry with the Gentiles and afterward turns inward towards the Jews (toward Jerusalem).