Parashas Bamidbar · Passuk 4:16
Responsibility shall rest with Eleazar son of Aaron the priest for the lighting oil, the aromatic incense, the regular grain offering, and the anointing oil—responsibility for the whole Tabernacle and for everything consecrated that is in it or in its vessels.
Chabad.org — English translation + Rashi
Source: Yoma 22b.
English: “And the charge of Elazar” — one who carries out on Shabbos, whether in his right hand or his left, in his bosom or on his shoulder, is liable, for thus was the burden of the sons of Kehas.
In context: The full range of carrying positions is validated by the way the sacred burdens were transported.
Custom
Chazal expand the liability for carrying on Shabbos from the model of the Kehasite burden.