Matthew 4:16

The people which sat in darkness saw great light; and to them which sat in the region and shadow of death light is sprung up--The prophetic strain to which these words belong commences with the seventh chapter of Isaiah, to which the sixth chapter is introductory, and goes down to the end of the twelfth chapter, which hymns the spirit of that whole strain of prophecy. It belongs to the reign of Ahaz and turns upon the combined efforts of the two neighboring kingdoms of Syria and Israel to crush Judah. In these critical circumstances Judah and her king were, by their ungodliness, provoking the Lord to sell them into the hands of their enemies. What, then, is the burden of this prophetic strain, on to the passage here quoted? First, Judah shall not, cannot perish, because IMMANUEL, the Virgin's Son, is to come forth from his loins. Next, one of the invaders shall soon perish, and the kingdoms of neither be enlarged. Further, while the Lord will be the Sanctuary of such as confide in these promises and await their fulfilment, He will drive to confusion, darkness, and despair the vast multitude of the nation who despised His oracles, and, in their anxiety and distress, betook themselves to the lying oracles of the heathen. This carries us down to the end of the eighth chapter.

— Jamieson-Fausset-Brown Commentary (public domain)