Jamieson, Fausset and Brown on Malachi 1:10

10. Who ... for naught--Not one even of the least priestly functions (as shutting the doors, or kindling a fire on the altar) would ye exercise without pay, therefore ye ought to fulfil them faithfully (1Co 9:13). Drusius and Maurer translate, "Would that there were absolutely some one of you who would shut the doors of the temple (that is, of the inner court, in which was the altar of burnt offerings), and that ye would not kindle fire on My altar in vain!" Better no sacrifices than vain ones (Is 1:11-15). It was the duty of some of the priests to stand at the doors of the court of the altar of burnt offerings, and to have excluded blemished victims [Calvin].