Matthew 24:21-22

for there shall be then great affliction, such as has not been from the beginning of the world unto this time, no, nor ever shall be.

Mark 13:19

for in those days shall be such affliction as never was from the beginning of the world, unto this day, nor ever shall be.

Acts 2:20

The sun shall be turned into darkness, and the moon into blood, before that great and illustrious day of the Lord come.

Romans 11:26

And so all Israel shall be saved, as it is written, "The deliverer shall come out of Sion, and shall turn away impiety from Jacob:

Revelation 6:17

for the great day of his wrath is come, and who can stand before Him?"

Treasury of Scripture Knowledge

Summary

Alas! for that day is great, so that none is like it: it is even the time of Jacob's trouble; but he shall be saved out of it.

Bible References

For

Acts 2:20
The sun shall be turned into darkness, and the moon into blood, before that great and illustrious day of the Lord come.
Revelation 6:17
for the great day of his wrath is come, and who can stand before Him?"

So

Matthew 24:21
for there shall be then great affliction, such as has not been from the beginning of the world unto this time, no, nor ever shall be.
Mark 13:19
for in those days shall be such affliction as never was from the beginning of the world, unto this day, nor ever shall be.

But

Romans 11:26
And so all Israel shall be saved, as it is written, "The deliverer shall come out of Sion, and shall turn away impiety from Jacob: