In these passages, day and time mean the Lord’s Coming. A day or time of darkness, gloom, thick darkness, no light, devastation, the iniquity of the end, or destruction means the Lord’s Coming, when he is no longer recognized and therefore when there is nothing left of the church.
A day that is cruel or terrifying, a day of blazing anger, wrath, panic, visitation, sacrifice, retribution, distress, war, or shouting means a coming of the Lord for judgment.
A day when Jehovah alone will be exalted, when he will be one and his name one, when the branch of Jehovah will be beautiful and glorious, when the righteous will flourish, when he will bring [a young cow and two sheep] to life, when he will search for his flock, when he will make a new covenant, when the mountains will drip with new wine, when living waters will go forth from Jerusalem, and when people will look back to the God of Israel (and many similar expressions) mean the Coming of the Lord to set up a new church that will recognize him as Redeemer and Savior.
from The Lord, Section 5