For at that time there will be great tribulation, unmatched from the beginning of the world until now, and never to be seen again.

Ezekiel 5:9
Because of all your abominations, I will do to you what I have never done before and will never do again.

Daniel 12:1
"At that time Michael, the great prince who stands watch over your people, will rise up. There will be a time of distress, the likes of which will not have occurred from the beginning of nations until that time. But at that time your people--everyone whose name is found written in the book--will be delivered.

Joel 2:2
a day of darkness and gloom, a day of clouds and blackness. Like the dawn overspreading the mountains a great and strong army appears, such as never was of old, nor will ever be in ages to come.

Matthew 24:20
Pray that your flight will not occur in the winter or on the Sabbath.

Matthew 24:29
Immediately after the tribulation of those days: 'The sun will be darkened, and the moon will not give its light; the stars will fall from the sky, and the powers of the heavens will be shaken.'

Revelation 7:14
"Sir," I answered, "you know." So he replied, "These are the ones who have come out of the great tribulation; they have washed their robes and made them white in the blood of the Lamb.

Revelation 16:18
And there were flashes of lightning, and rumblings, and peals of thunder, and a great earthquake the likes of which had not occurred since men were upon the earth--so mighty was the great quake.

For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.