'Day' in the Bible

when He comes to be glorified in His saints on that day, and to be marveled at among all who have believed—for our testimony to you was believed.

that you not be quickly shaken from your composure or be disturbed either by a spirit or a message or a letter as if from us, to the effect that the day of the Lord has come.

nor did we eat anyone’s bread without paying for it, but with labor and hardship we kept working night and day so that we would not be a burden to any of you;