This sugya focuses on the primary role of the Mezuzah.  The purpose of a Mezuzah is to remind us, each time we pass through a doorway, about the contents of the Parshiyos contained within – namely, the declaration of the Oneness of Hakadosh Baruch Hu, and the obligation to love Hashem, etc.  

However, the Gemara states that the Mezuzah also provides shemirah (protection) to the home.  The minhag is that the name of Hashem Sha-dai is written on the back of the klaf and acts as a shemira over the home’s occupants.  Additionally, other phrases which provide shemirah are written on the klaf (Kuzu Bimuksaz Kuzu).  Even so, some Poskim maintain that one should not perform the Mitzvah of Mezuzah for the reasons of shemirah, but rather only to fulfill Hashem’s Mitzvos – as the shemirah is intrinsic to the Mitzvah and happens automatically.

Among the questions discussed:

• What should one’s kavana be when passing through a doorway?
• ·         Is it proper to put up a Mezuzah for reasons of shemira?
• ·         Why does a renter put up the Mezuzah, and not the homeowner?
• ·         Why is one not allowed to remove his Mezuzos when one moves from his home?
• ·         Is a child’s room obligated for a Mezuzah because of shemira?  (i.e. as the child is not mechuyav in Mitzvos)
• ·         If one neglects to place a Mezuzah, and a robbery occurs, can he be considered a “posheia” and be responsible for the theft (similar to not locking a door)?
• ·         What is the significance of the name “Sha-kai” on the Mezuzah?
• ·         May one give a Mezuzah to a non-Jew as shemirah for the non-Jew’s property?
•    May one use a Mezuzah as a kamea (amulet)?