Parashas Vayakhel · Passuk 35:2
Torah Temimah points to classical source on this unit (verified).
English: “It shall be holy for you” means holy with respect to you, while ordinary work remains permitted for the sake of the sacred service.
Derash distinguishing ordinary Shabbos labor from sacred service that is performed on Shabbos.
The Mechilta distinguishes ordinary human labor from Temple sacrificial service, which may be performed on Shabbos when its time requires it.