"Judges and officers you shall place at all your city-gates..." (Deuteronomy 16:18). The human body is a city with seven gates--seven portals to the outside world: the two eyes, two ears, two nostrils and the mouth. Here, too, it is incumbent upon us to place internal "judges" to discriminate and regulate what should be admitted and what should be kept out, and "officers" to enforce the judges' decisions...
Rabbi Shabtai HaCohen ("Shach"), 1622-1663