'Day' in the Bible

in that day when He comes to be glorified by His saints and to be admired by all those who have believed, because our testimony among you was believed.

not to be easily upset in mind or troubled, either by a spirit or by a message or by a letter as if from us, alleging that the Day of the Lord has come.

Don’t let anyone deceive you in any way. For that day will not come unless the apostasy comes first and the man of lawlessness is revealed, the son of destruction.

we did not eat anyone’s food free of charge; instead, we labored and struggled, working night and day, so that we would not be a burden to any of you.