5:2

Jehovah’s day: Throughout the Scriptures, the expression “Jehovah’s day” (or “the day of Jehovah”) refers to special times when Jehovah God executes judgment on his enemies and glorifies his great name. The expression has its background in the Hebrew Scriptures. (Some examples are found at Isa 13:6; Eze 7:19; Joe 1:15; Am 5:18; Ob 15; Zep 1:14; Zec 14:1; Mal 4:5.) The prophet Joel speaks about “the coming of the great and awe-inspiring day of Jehovah.” (Joe 2:31) This scripture is quoted by Peter at Pentecost 33 C.E., as recorded at Ac 2:20. (See study note on Ac 2:20.) In the first fulfillment of Joel’s prophecy, that “day of Jehovah” came upon Jerusalem in the year 70 C.E. Here at 1Th 5:2, Paul speaks of a future day of Jehovah that corresponds to the “great tribulation” that Jesus foretold at Mt 24:21.​—For the use of the divine name in this verse, see App. C3 introduction; 1Th 5:2.

as a thief in the night: Thieves will typically strike at night, quickly and unexpectedly. (Job 24:14; Jer 49:9; Mt 24:43) Likewise, Jehovah’s day will strike suddenly, taking people by surprise. (2Pe 3:10; Re 16:15) Faithful Christians obey the counsel to live in expectation of that day. (Lu 12:39; Re 3:3) While they too may be surprised by the sudden start of that day (Mt 24:42-44; Lu 12:40), they will not be caught off guard when it arrives (1Th 5:4).