The Dish of Shabbat that Gives off a Fragrance
Legend Book – Bavli Shabbat 119:1
The Caesar said to Rabbi Yehoshua the son of Chananya: "Why does the food of Shabbat give off such a fragrance?"
He responded: "We have a spice, whose name is Shabbat, we put it in the dish and its fragrance spreads out."
He told him: "Give me some of it."
He replied: "This spice can only be useful to those who observe Shabbat and it is of no benefit to those who do not observe Shabbat."