One of the zemirot traditionally sung on Shabbat begins with the words “ki eshmera Shabbat,” meaning “for I will keep Shabbat.” This poem was composed by Rabbi Avraham ibn Ezra (1089 – ca. 1167), a Spanish astronomer and mathematician, grammarian and biblical commentator, and of course poet.
The poem is an acrostic, meaning that the first letter of the five stanzas spell out the Hebrew name Avraham, indicating Ibn Ezra’s authorship. It compares actions that are forbidden on Shabbat to things we do to make Shabbat special. The final stanza, however, has a cryptic line. The last stanza begins by reminding readers that one who does melacha, or defined types of work, on Shabbat can expect karet (Exodus 31:14). Karet is a mysterious punishment that the sages explain involves premature death and consequences in the world of souls. The poem continues: “Therefore I will wash my heart with it like soap.” This is a strange simile to describe how we wash us our hearts: We don’t wash soap!
To be sure, some versions of the poem use a different preposition: “Therefore I will wash my heart with it, with soap.” While this alternate version makes sense and may be the authentic text, it is not the prevalent version sung around Shabbat tables.
What does it mean to wash “like soap”? Hassidic masters offered different explanations for this cryptic line; here I will recount three possible readings.
Rabbi Avraham of Slonim (1803-1883), founder of the Slonim Hassidic dynasty in Lithuania, focused on the next line of the poem: “I will pray to God in the evening service and the morning service, the additional service and the afternoon service, too; He will answer me.” Just like soap removes stains from clothing, explained Rabbi Avraham, so too Shabbat prayers remove stains from the heart. According to this reading, the last stanza should be read thus: Therefore, I will wash my heart with prayers to God. These prayers act like cleansing soap.
A different reading is credited separately to two hassidic masters – to Rabbi Yitzhak Eizek Taub of Kaliv (1751-1821), a central figure in Hungarian hassidic lore; and to Rabbi Zvi Hersh Hakohen of Rymanov (1778-1846), a Galician hassidic master. Shabbat presents an opportunity for people to cleanse their hearts in a deep and meaningful way, to the extent that their hearts are not only unsullied, but they even turn to soap. “Like soap,” therefore, refers to the heart – not to the act of washing – and the line describes the state of the heart after it has been washed by Shabbat. These Shabbat-inspired “soap hearts” then have the capacity to cleanse other hearts!
In this vein, the Tzadik of Kaliv saw it as his duty to spiritually wash, cleanse and purify his charges. Once, the Tzadik of Kaliv turned to one of his students and said: “Do you know how I made you into a real Jew? I took your soul out of you and washed it, scrubbing it clean, just like a washerwoman scrubs the laundry until it is spotless!”
A third explanation was set forth by Rabbi Meir’l of Przemyslany (1783-1850), a hassidic master famous for his miracle-working capabilities. He suggested that Shabbat itself is the soap. As if to say: “Therefore I will wash my heart with Shabbat, just as I wash with soap.” Shabbat is the cleansing agent that washes the heart.
In modern parlance, the term “Shabbat soap” is often used to denote liquid soap. According to Jewish law, the use of a bar of soap is forbidden on Shabbat. This is because when lathering, we rub the top layer away and smooth the surface of the soap – an act prohibited on Shabbat. The widely accepted – and hygienic – solution is to use liquid soap, or “Shabbat soap,” which lathers while avoiding the problematic solid bar.
Considering the Ibn Ezra’s poem and the hassidic interpretations gives the term “Shabbat soap” additional connotations: the Shabbat prayers are cleansing soap, Shabbat turns our hearts to soap that can then cleanse others, or possibly Shabbat itself is some type of spiritual soap!