'Great Tribulation' in the Bible

For there will be then, Great tribulation, such as hath not happened, from the beginning of the world, until the present time, neither in any wise shall happen.

And there came a famine upon all Egypt and Canaan, and great tribulation, and our fathers could not find pasture.

Lo! I cast her into a bed, and them who are committing adultery with her, into great tribulation, - except they repent out of her works;

And I at once said to him - My lord! thou, knowest! And he said unto me - These, are they who come out of the great tribulation, and they washed their robes, and made them white in the blood of the Lamb;