Tabernacle: The Priests: Alone Could Enter
Source: TTT
Numbers 18:3, 5
And they shall attend to your duties and to all the duties of the Tent; but they must not come near to the furnishings of the sanctuary or the altar, or both they and you will die. / And you shall attend to the duties of the sanctuary and of the altar, so that wrath may not fall on the Israelites again.