What does Matthew 4:16 mean?

Matthew is quoting from Isaiah 9:1–2 to show that Jesus' move to Capernaum on the Sea of Galilee was another fulfillment of prophecy about the Messiah. Capernaum and the region around it fell within the ancient boundaries of the Jewish tribes of Zebulun and Naphtali.

The people of that land were described as dwelling in darkness under the shadow of death during Isaiah's time. This was likely true for several reasons. First, their land was much closer to Gentile peoples and thus more vulnerable to attack. Second, the people living there were far away from the cultural and religious centers of Jerusalem and Judea. They had to travel some distance to reach the temple and the dwelling place of God.

Isaiah's prophecy, though, while writing about the coming of the Messiah, was that a light would dawn in their region. Matthew shows that Jesus is that light. He shines brightly in the land of darkness known then as "Galilee of the Gentiles." Instead of coming first to the "well lit" region of Judea, Christ comes first to the people living in darkness.

Isaiah 9 is often read around Christmas time. Though the prophecy was about the peoples of Zebulun and Naphtali, it is also true that the birth of Jesus brought light into a world of darkness. A few verses later, Isaiah 9:6 famously says of the Messiah, "For to us a child is born, to us a son is given; and the government shall be upon his shoulder, and his name shall be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace."