Matthew 24:21-22

for there will be greater misery at that time than ever has been since the world began, or ever will be again.

Mark 13:19

for there will be such misery at that time as has never been since the beginning of God's creation, and never will be again.

Acts 2:20

The sun will turn to darkness, and the moon to blood, before the coming of the great and glorious day of the Lord.

Romans 11:26

and so in that way all Israel will be saved, just as the Scripture says: "From Zion the Deliverer will come; He will remove ungodliness from Jacob;

Revelation 6:17

because the great day of their anger has come, and who can stand it?"

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 will turn to darkness, and the moon to blood, before the coming of the great and glorious day of the Lord.
Revelation 6:17
because the great day of their anger has come, and who can stand it?"

So

Matthew 24:21
for there will be greater misery at that time than ever has been since the world began, or ever will be again.
Mark 13:19
for there will be such misery at that time as has never been since the beginning of God's creation, and never will be again.

But

Romans 11:26
and so in that way all Israel will be saved, just as the Scripture says: "From Zion the Deliverer will come; He will remove ungodliness from Jacob;