'Day of the Lord' in the Bible

The sun shall become darkness, and the moon blood-red, Before the Day of the Lord comes--that great and awful day.

To deliver such a man as this over to Satan, that what is sensual in him may be destroyed, so that his spirit may be saved at the Day of the Lord.

You yourselves know well that the Day of the Lord will come just as a thief comes in the night.

Not lightly to let your minds become unsettled, nor yet to be disturbed by any revelation, or by any message, or by any letter, purporting to come from us, to the effect that the Day of the Lord is come.

The Day of the Lord will come like a thief; and on that day the heavens will pass away with a crash, the elements will be burnt up and dissolved, and the earth and all that is in it will be disclosed.