זֹ֣את עֲבֹדַ֔ת מִשְׁפְּחֹ֖ת הַגֵּרְשֻׁנִּ֑י לַעֲבֹ֖ד וּלְמַשָּֽׂא׃
This is the service of the families of the Gershonites, in serving and in bearing burdens:
Targum Jonathan on Numbers
And this is the service of the family of Gershon, to serve and to carry.