In the book of Isaiah chapters 7-12, the prophet speaks of the salvation of Israel from its enemies, with the person of the Messiah in view as a central theme to these chapters.
Isaiah 9:1-2 ...but in the latter time he has made glorious the way of the sea, the land beyond the Jordan, Galilee of the nations. The people who walked in darkness have seen a great light; those who dwelt in a land of deep darkness, on them has light shone.
Matthew chapter 4 portrays Jesus’ ministry in Galilee as the ultimate fulfillment of this prophecy.
Matthew 4:13-16 And leaving Nazareth he went and lived in Capernaum by the sea, in the territory of Zebulun and Naphtali, 14 so that what was spoken by the prophet Isaiah might be fulfilled: 15 “The land of Zebulun and the land of Naphtali, the way of the sea, beyond the Jordan, Galilee of the Gentiles— 16 the people dwelling in darkness have seen a great light, and for those dwelling in the region and shadow of death, on them a light has dawned.”
Isaiah is speaking of the messianic light, fulfilled in Jesus who sheds his light both on the Jewish people and on the nations of the world. The theme of Jesus as the light is prominent in the New Testament. In the gospel of John says.
John 1:4-5 “In him was life, and the life was the light of men [i.e., people]. The light shines in the darkness, and the darkness has not overcome it.”
Jesus the light
In John 8:12, Jesus himself says, “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life,” while in John 9:5, he declares that, “As long as I am in the world, I am the light of the world.” Yet again, in John 12:46, he says, “I have come into the world as light.”
The people walking in darkness have seen a great light; on those living in the land of deep darkness a light has dawned.
The Messiah would bring light to Galilee