Midrasch zu Wajikra 13:54

4) (Vayikra 13:53) "And the Cohein shall see, and, behold, the plague-spot has not spread in the garment, or in the warp or in the woof, or in any article of skin": This refers to the stationariness (omed) of the plague-spot, (and not to the non-appearance of a different plague-spot). (Vayikra 13:54) ("Then the Cohein shall command, and they shall wash what contains the plague-spot, and he shall quarantine it a second seven days.") "Then the Cohein shall command and they shall wash": the command, by the Cohein; the washing, by any man.