Isaiah 13:10
For the stars of heaven and the constellations thereof shall not give their light: the sun shall be darkened in his going forth, and the moon shall not cause her light to shine. For the stars of heaven and the constellations thereof shall not give their light: the sun shall be darkened in his going forth, and the moon shall not cause her light to shine.
The verse foretells fearful signs accompanying the day of the Lord. The stars of heaven and their constellations will withhold their light, the sun will be darkened in its going forth, and the moon will not cause its light to shine. That darkening belongs to the portrayal of the day of the Lord as destruction from the Almighty, bringing terror and distress. It comes when God punishes the world for its evil and the wicked for their iniquity, destroys sinners and the unrepentant, lays low the proud and haughty, and makes the land desolate.
This day of wrath is the time of the seven last plagues, placed before Christ's second coming. It is also the final destruction of those who refuse Christ. That destruction comes by fire from heaven outside the city of God at the close of the thousand years.