"from all of Israel wherein he lives": in all of the places of their dwellings":
Whence is it derived that a Cohein may come and offer his (own) sacrifices whenever he wishes (though his watch not be officiating at that time)? From "then he shall come in all the desire of his soul … (7) and he shall serve." Whence is it derived that a Cohein may come and lift his hands (in the priestly blessing) in a watch that is not his? From "then he shall come in all the desire of his soul … and he shall serve in the name of the L-rd his G-d." Which is service in the name of the L-rd? The priestly blessing.