The Magic Mezuzah
It is said that having a mezuzah on your door will protect your home, just as wearing the talit katan will protect your person. First let me say that I do not doubt either of these statements. What has puzzled me was what was meant by “protection” and how exactly that protection was affected. Was protection to be understood as a metaphor? Meaning to guard your behavior? Seeing the mezuzah or the tzitzit would then merely be a reminder to stay on track and behave properly as a Jew. Thus your life as a Jew would be protected from outside influences. Or perhaps protection is meant literally. The mezuzah functions as an amulet putting some sort of mystic shield around your home.
Now I hold with the literal understanding of protection, but as to how it functioned I did not know. Maybe angelic powers were invoked by the hanging of the mezuzah, maybe the parchment itself emitted protective energy. Then I came across this passage:
Rabbi Abba said, “In so many places the blessed Holy One cares for His children! A person builds a house; the blessed Holy One says to him, ‘Write My name and place it at the entrance. You dwell within your house, and I will sit outside at your entrance to protect you.’
Zohar 2:36A Pritzker Edition, Daniel Matt, p. 161.
Ah, Hashem Himself guards those that fulfill his commandments.