Matthew 24:21-22

For then there will be great tribulation, such as has not been from the beginning of the world even until now nor ever may be.

Mark 13:19

For these days will be tribulation, such as has never been from the beginning of creation which God created, until now, and never may be.

Acts 2:20

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

Romans 11:26

and so all Israel shall be saved: as has been written, A leader shall come out of Zion, shall turn ungodliness from Jacob.

Revelation 6:17

because the great day of their wrath has come; and who is able to stand?

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 the great day of the Lord shall come.
Revelation 6:17
because the great day of their wrath has come; and who is able to stand?

So

Matthew 24:21
For then there will be great tribulation, such as has not been from the beginning of the world even until now nor ever may be.
Mark 13:19
For these days will be tribulation, such as has never been from the beginning of creation which God created, until now, and never may be.

But

Romans 11:26
and so all Israel shall be saved: as has been written, A leader shall come out of Zion, shall turn ungodliness from Jacob.