Or HaChaim on Exodus 30:21/אור החיים על שמות ל׳:כ״א

1 חק עולם, an eternal law. Even though the priest may have just emerged from immersing himself in a ritual bath in order to purify himself from a more severe category of impurity, this does not relieve him of the need to wash his hands and feet from the water of the כיור. The Torah warns the priest for the fifth time not to risk the death penalty to warn him that the ritual immersion did not replace the commandment to wash their hands and feet before either entering the Sanctuary or approaching the copper altar in the courtyard to perform service therein.