(In memory of my grandfather, Mordechai ben Eliyahu ha-Kohen, a”h.)
Q: What is the reason that the Divine name “Sha-dai” is inscribed on the outside of a mezuzah scroll?
A: The Torah refers to G-d by a number of names. One ought to ask the more basic question: Why does G-d have so many names?
We cannot know the essence of G-d. As mere mortals, we cannot fathom His Infinity. However, we do experience the Almighty inasmuch as we are aware of His actions. The “names” of G-d function as labels for particular types of G-d’s interactions with the world
The Gaon of Vilna, in his commentary to the Book of Ruth (1:1), cites the teaching of our Sages that the name “Sha-dai” refers, in abbreviation, to “the One Who said, ‘Enough'” (“She-Amar Dai”). This name describes G-d inasmuch as He sets boundaries and limitations in the world, “laws” of nature, as it were. The Hebrew word “din,” meaning “law,” is based on the word “dai.” The laws of physics and the entire naturalistic system that guides our physical world emanate from this name.
Conversely, the four-letter Name, or Tetragrammaton, comprised of the letters “yud,” “heh,” “vav” and “heh,” which form the words “hayah” (“was”), “hoveh” (“is”), and “yihyeh” (will be), indicates G-d’s infinity and unlimited capacity, as One Who transcends even the bounds of eternity. G-d’s abundant will and capacity to give emanates from this name. This name appears within the sections of text inscribed on the inside of the mezuzah scroll.
Every human being has a dual capacity — that of the spirit and that of the body. One’s spiritual wealth derives from one’s relationship to G-d, through one’s fulfillment and study of the Torah. One’s physical wealth resides in one’s worldly assets and indulgences. One’s spiritual self is one’s “inner” being while one’s physical identity forms one’s “outer” being.
In elevating man above the animals, G-d’s plan calls for man to curtail his animal component, the body, and develop his G-dly component, the soul; he should limit his outer being and expand his inner being. Therefore, explains the Gaon, as a sign to mankind to follow this Divine directive, G-d commands that we install the mezuzah upon our doorways and gateways, the threshold between inside and outside. The inside of the mezuzah contains the four-letter Name, indicating our obligation to develop and expand our inner self in an unlimited fashion, forming as strong a bond to our Creator as possible. The outside of the mezuzah bears the name “Sha-dai,” reminding us to place limitations on our physical indulgences in order to elevate ourselves above the natural world. In combination, these two strategies lead to spiritual success and fulfillment of the human mission.
May we merit to internalize the message of the mezuzah’s design, crossing the threshold between outer and inner realms to realize the infinite potential within.
ADDENDUM: Instances I came across since the writing of this article in which “Sha-dai” is used to indicate meting of law or justice:
Isaiah 13: “Cry out, for the day of G-d (Yud-Heh-Vav-Heh) draws close; like a pillaging from G-d (Sha-dai) comes.” (This section of Isaiah speaks of the punishment that is to come upon Babylonia for its destruction of Judah and Jerusalem.)