To meet Yofiel, the angel of Torah, to ward off the devil, or to pronounce God's name are some reasons for ascetic fasting. But beware: Publicizing your fast not only negates your act of piety but can bring down divine wrath. Just ask Miriam daughter of Onion Leaf.
Biblical prohibitions against preparing food on Shabbat are further developed in the Second Temple and rabbinic periods. At the same time, a new emphasis emerges: celebrating Shabbat with festive meals.
Sarit Kattan Gribetz