Isaiah 8:22
And they shall look unto the earth; and behold trouble and darkness, dimness of anguish; and they shall be driven to darkness. And they shall look unto the earth; and behold trouble and darkness, dimness of anguish; and they shall be driven to darkness.
Those who look to the earth find only trouble and darkness, dimness of anguish, and are driven on into deeper darkness. Turning away from God's instruction to seek other guidance leads to that distress, anguish, and deepening darkness. The immediate setting was Judah's apostasy and oppression in the later years of Ahaz, when Judah would suffer under Assyria and other nations and eventually go into captivity. That chastisement would serve as a means of salvation, and with promises of restoration and future triumph hope remained bright even in that dark period.
On the widest scale the trouble, darkness, and anguish span human history from Adam and Eve's loss of Eden until Christ appeared as Saviour, where the darkness is the fallen race's bondage to sin and the grave amid which people hoped for a Deliverer. Just before the Messiah's advent many who longed for truth were led astray by false teaching and false teachers into philosophy and spiritism, while others had only an outward form of godliness without true holiness, leaving the outlook dark and seemingly hopeless. The outlook remained hopeless until the Messiah, the Sun of Righteousness, brought light and healing.