'Burdens' in the Bible

This is the service of the families of the Gershonites, to serve, and for burdens:

At the appointment of Aaron and his sons shall be all the service of the sons of the Gershonites, in all their burdens, and in all their service: and ye shall appoint unto them in charge all their burdens.

from thirty years old and upward even unto fifty years old, every one that entered in to do the work of service, and the work of bearing burdens in the tent of meeting,

And Moses said to Yahweh, "Why have you brought trouble to your servant? Why have I not found favor in your eyes, that the burdens of all these people have been placed on me?

I will come down and speak with you there; I will take away from the spirit that [is] on you, and I will place [it] on them; and they will bear the burdens of the people with you; you will not bear it alone.