Hebrews 10:19-20

Having, therefore, brethren, boldness for the entrance into the holy places by the blood of Jesus,

Revelation 11:19

And the Temple of God that is in Heaven was opened, and the ark of His covenant was seen in His Temple; and there were lightnings, and voices, and thunders, and an earthquake, and 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
Having, therefore, brethren, boldness for the entrance into the holy places by the blood of Jesus,
Revelation 11:19
And the Temple of God that is in Heaven was opened, and the ark of His covenant was seen in His Temple; and there were lightnings, and voices, and thunders, and an earthquake, and great hail.