The Connection Between Shemiras Halashon and Mezuzah

The Connection Between Shemiras Halashon and Mezuzah:

The Chasam Sofer zy”a (Sefer Toras Moshe) writes that one reason why we place a mezuzah on our doorpost is to symbolize that one must sanctify the “door” to his body (i.e., his mouth) if he wants his entire body to be holy. Even if a house is full of sefarim, it still needs a mezuzah. So too, even if one is full of Torah, he still needs to guard his mouth in order to be holy. And even if a house is not full of sefarim, the mezuzah sanctifies the house. So too, even if a person is not full of Torah and yiras shomayim, if his mouth is protected and kept holy, he is considered to be a sanctified person. This is because the mouth defines a person.