פירוש על במדבר 4:24

לעבוד ולמשא. The former, לעבוד, while the people were encamped; the latter while the people were journeying. ולמשא, at the time of the journeys. Seeing that earlier when the Torah said:ומשמרת בני גרשון באהל מועד, (3,25) it spoke about their carrying out their function at the time of the people being encamped, the Torah also stated that everything which was under their control while the people were encamped remained under their control during the journeys.