Original Verse:
Exodus Chapter 28 Verse 35Aaron is to put it on for his holy work; and the sound of it will be clear, when he goes into the holy place before the Lord, and when he comes out, keeping him safe from death.

Reference Verses:
Leviticus Chapter 16 Verse 2The Lord said to Moses, Say to Aaron, your brother, that he may not come at all times into the holy place inside the veil, before the cover which is on the ark, for fear that death may overtake him; for I will be seen in the cloud on the cover of the ark.
Hebrews Chapter 9 Verse 12And has gone once and for ever into the holy place, having got eternal salvation, not through the blood of goats and young oxen, but through his blood.