en_tn_lite_do_not_use/mat/04/16.md

The people who sat

These words can be combined with the sentence beginning with "The land of Zebulun" (verse 15). Alternate translation: "In the territory of Zebulun and Naphtali ... where many Gentiles live, the people who sat"

The people who sat in darkness have seen a great light

Here "darkness" is a metaphor for not knowing the truth about God. And "light" is a metaphor for God's true message that saves people from their sin. (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 "those who sat in the region and shadow of death" is a metaphor. It represents those who did not know God. These people were in danger of dying and being separated from God forever. (See: rc://en/ta/man/translate/figs-parallelism and rc://en/ta/man/translate/figs-metaphor)