These territories describe the same area. The list of territories can be included in the following sentence. AT: "In the territory of Zebulun and Naphtali ... in the territory of Galilee where many Gentiles live, the people who sat"
# The people who sat in darkness have seen a great light
Here "darkness" refers to moral darkness or sin, which separates people from God. And, "light" refers to God's true message that saves people from their sin. This is the image of people who were without hope now having hope coming from God. (See: [[rc://en/ta/man/translate/figs-metaphor]])
# to those who sat in the region and shadow of death, upon them has a light arisen
This basically has the same meaning as the first part of the sentence. Here "region and shadow of death" refers to spiritual death or a separation from God. (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-metaphor]])