“Now on the topic of times and seasons, brothers and sisters, you have no need for anything to be written to you. For you know quite well that the day of the Lord will come in the same way as a thief in the night” (1 Thessalonians 5:1-2 NET).
The “day of the Lord” is a phrase that merits close attention for it is a term appears with considerable frequency in the pages of the Scriptures. For instance, this phrase is used in both the Old and New Testaments to describe God’s wrath (Isaiah 13:9), God’s judgment (as we’ll see next in 1 Thessalonians 5:3), a time of destruction (Joel 1:15), and a day of recompense for those who have done wrong (Obadiah 1:15).
The prophet Joel also described the day of the Lord as “great and very terrible” in Joel 2:11. However, Joel was not alone in this characterization, for the Old Testament prophets Ezekiel, Amos, Zephaniah, and Malachi associate the “day of the Lord” with similar words like, “doom,” “darkness,” “trouble and distress,” and “dreadful.”
Here in 1 Thessalonians 5:2, the day of the Lord is associated with the events that will accompany Jesus’ return. Three commentators provide some additional insight into the use of this important term…
“The prominent idea associated with that Day in the Old Testament, and in this passage as well, is that of ‘judgment’ and destruction upon the enemies of God. This stands in striking contrast to the previous passage (4:13–18), where the emphasis was hope and resurrection. The difference of course is one of focus; it depends upon whether believers or unbelievers are in view.” (1)
“In the OT the writers saw two ages, an evil age and a coming age of righteousness, the age of the Spirit. God would intervene in history through His Messiah to set up this new age. This event was known as the ‘Day of the Lord.’ Notice that NT writers attribute this to Christ. His first coming, the Incarnation, was foretold in many OT texts. The Jews did not expect a divine person, just a divine intervention. The two comings of the Messiah, one as suffering servant and savior, one as Judge and Lord, were not obvious to OT people.” (2)
“Christ has already passed through the judgment of the day of the Lord for believers, so they need not fear His return (Heb. 9:27, 28). Unbelievers, however, will feel the wrath of God when the day of the Lord is consummated at the second coming of Christ.” (3)
(1) Hindson, E. E., & Kroll, W. M. (Eds.). (1994). KJV Bible Commentary (p. 2480). Nashville: Thomas Nelson.
(2) Dr. Bob Utley. Free Bible Commentary, 1 Thessalonians 5:2 Copyright © 2014 Bible Lessons International http://www.freebiblecommentary.org/new_testament_studies/VOL07/VOL07B_05.html
(3) Sproul, R. C. (Ed.). (2015). The Reformation Study Bible: English Standard Version (2015 Edition) (p. 2138). Orlando, FL: Reformation Trust.