Mezuzah ש‎

The Hebrew letter ש‎ (Shin) reflects the name of God. On the back of the klaf (parchment), this name of God, Shaddai (“Almighty”), is inscribed. The three letters of this name form an acronym for the Hebrew phrase Shomer Daltot Yisrael, meaning “Guardian of the doorways of Israel.” Hashem promises to protect and watch over the home of a Jew who affixes the mezuzah on his doorway. On the other side of the mezuzah, the two paragraphs of the Shema are written.