Hebrews 10:19-20

Then, brethren, having boldness unto the entering in of the holies through the blood of Jesus,

Revelation 11:19

And the temple of God was opened in the heaven and the ark of His covenant was seen in his temple, and there were lightnings, and voices, and thunders, and earthquakes, and a great hail.

Treasury of Scripture Knowledge

Summary

But they shall not go in to see when the holy things are covered, lest they die.

Bible References

They shall

Hebrews 10:19
Then, brethren, having boldness unto the entering in of the holies through the blood of Jesus,
Revelation 11:19
And the temple of God was opened in the heaven and the ark of His covenant was seen in his temple, and there were lightnings, and voices, and thunders, and earthquakes, and a great hail.