Numbers 4:3-5

Amplified Bible

³ from thirty years old and upward, even to fifty years old, all who enter the service to do the work in the Tent of Meeting (tabernacle). ⁴ This is the work and responsibility of the sons of Kohath in the Tent of Meeting (tabernacle): the most holy things.

⁵ “When the camp prepares to move out, Aaron and his sons shall come into the sanctuary and take down ^[a]the veil (curtain) screening off the Holy of Holies, and cover the ark of the testimony with it;