Lighting a fire and cooking food are among the activities prohibited on Shabbat by the written Torah. Therefore, cooked Shabbat food, such as cholent or hamin, must be prepared before the onset of the Jewish Shabbat – by some as early as Thursdays and certainly not later than Friday afternoon. The pre-cooked food may then be kept hot for the Shabbat meal by the provision in the Rabbinical oral law, which explains that one may use a fire that was lit before Shabbat to keep warm food that was already cooked before Shabbat.