According to Isaiah, even though things were tough for the people living in certain places, like Zebulun and Naphtali, a better and brighter time is coming. It's like when you feel sad but then something good happens to make you feel happy again.
Isaiah 9:1: Nevertheless the dimness [shall] not [be] such as [was] in her vexation, when at the first he lightly afflicted the land of Zebulun and the land of Naphtali, and afterward did more grievously afflict [her by] the way of the sea, beyond Jordan, in Galilee of the nations. [of the nations: or, populous]
Isaiah 9:1 speaks of regions that were afflicted but will experience glory, while Matthew 4:16 refers to people sitting in darkness who see a great light.
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.