Submitted by Dr. GP
Many of the Old Testament prophets make reference to this momentous period of time. Some use the terms “the day” or “the great day” or “that day”, but all by this expression strongly relate to God’s rule of the earth and therefore to His sovereign purpose for world history and specific events within that history.
The Day of the Lord refers to God’s special interventions into the course of world events to judge His enemies, accomplish His purpose for history, and thereby demonstrate that He is the sovereign God of the universe. Diligent perusal of the pages of the Promises of God reveal that references to the Day of the Lord occur seventy-five times in the Old Testament. This phrase became such an understandable subject of the Old Testament that by the time of Zechariah, one of the last of the prophets, he could use the term “in that day” and it was understood that he meant the Day of the Lord.
This phrase had definite connotations and was the great theme of the writings of the Old Testament prophets, who related it to the future kingdom promised in the Old Testament, and connected it with the coming of Christ as it relates to the setting up of this kingdom. The expression “the day of the Lord” clearly has an end-time (eschatological) meaning.
Full Article – The Day of Our Lord