God’s name on a mezuzah scroll – Ask the Rabbi
Q. Why is the word Shaddai (Almighty) written on the back of the mezuzah parchment?
A. There are several possible reasons. The most obvious is that the mezuzah declares that the Almighty is present in that house or building.
Some say the name is short for the Hebrew words, Shomer Dal’tot Yisra’el, “Guardian of the Doors of Israel”.
Others prefer to see in the name the words, She’amar La’olam Dai (“He said to the world, ‘Enough!'”), which may signify the duty to protect oneself against infringing the privacy of others: gates and doors, after all, are both for security and privacy.

