Eleasar is entrusted to the oil from the light and the power of the candlesticks, the daily food offering and the anointing oil, and the oversight of the whole residence, including sacred devices.

God speaks to Moses and Aaron: You shall not bring the families of the Kohathites among the Levites, but instead go unto them yourselves: Aaron and his sons shall go in and do all the ministry and its payload at the liturgy. They, however, must not even go to watch the saints for even a moment, so that they do not perish.
And God spoke to Moses and said: Take the tribes of the sons of Gershon according to their gender; from thirty to fifty years old and put everyone at their liturgy, so they come to the service of the tabernacle. This shall bear the curtains of the tabernacle of the tent, cover it with the seal skin, the screen for the door of the tabernacle and the curtains of the court, and the curtain in the door of the gate surrounding the atrium of the tabernacle and the altar; their roles and all the instruments of their service, and all that belongs to their service. All services of the sons of Gershon and everything that they wear and do, you shall see to it that it is done under the direction of Ithamar, the son of Aaron.
Moreover, thou shalt screen the sons of Merari by their genders and clans from thirty to fifty years old. They are in the service of the boards of the tabernacle, the bars, pillars and bases, the pillars of the court, its base, pegs and ropes and all the equipment towards the demands of the liturgy under your allocation of equipment. Ithamar shall oversee them.