'Day' in the Bible

But who shall endure the day of his coming? and who shall stand when he appeareth? For he will be like a refiner's fire, and like fullers' lye.

And they shall be unto me a peculiar treasure, saith Jehovah of hosts, in the day that I prepare; and I will spare them as a man spareth his own son that serveth him.

For behold, the day cometh, burning as a furnace; and all the proud and all that work wickedness shall be stubble; and the day that cometh shall burn them up, saith Jehovah of hosts, so that it shall leave them neither root nor branch.

And ye shall tread down the wicked; for they shall be ashes under the soles of your feet in the day that I prepare, saith Jehovah of hosts.

Behold, I send unto you Elijah the prophet, before the coming of the great and terrible day of Jehovah.