Nevertheless the darkness shall not be as when the distress was in the [land], at the time he at first lightly, and afterwards heavily, visited the land of Zebulun and the land of Naphtali, the way of the sea, beyond the Jordan, Galilee of the nations:
Isaiah 9:1 Nevertheless the darkness shall not be as when the distress was in the [land], at the time he at first lightly, and afterwards heavily, visited the land of Zebulun and the land of Naphtali, the way of the sea, beyond the Jordan, Galilee of the nations:
Isaiah 9:2 the people that walked in darkness have seen a great light; they that dwelt in the land of the shadow of death, upon them light hath shone.
Isaiah 9:3 Thou hast multiplied the nation, hast increased its joy: they joy before thee like to the joy in harvest; as [men] rejoice when they divide the spoil.
The verse centers on "light", "darkness", "nevertheless", "shall", "distress", "land", "time", and "first". It is saying that the contrast between light and darkness marks a real divide in how people respond to God's work.
The next verse adds "the people that walked in darkness have...", so "light" and "darkness" should be read forward into that movement. In Isaiah context, the local focus is the Holy One of Israel, judgment and restoration, the servant of the LORD, and Zion's hope.
A plain takeaway is to answer the verse's own emphasis on "light" and "darkness" with trust shaped by these words, not by a vague optimism outside the passage.