A man must say three things in his home on the eve of the Sabbath just before dark: ‘‘Have you tithed? Have you prepared the eruv? Kindle the [Sabbath] light!’’ If there is a doubt whether it is dark or it is not dark, we may not tithe defi-nite[ly untithed produce], nor may we immerse vessels, nor may we kindle the lights; but we may tithe demai, make an eruv, and insulate hot food.

A double stove that was heated with straw or with stubble, we may place a cooked food upon it; [if it was heated] with marc or with wood, one may not place [cooked food upon it] until he has swept away [the coals], or until he has put ashes [over them]. Beis Shammai say: Hot water but not cooked food. But Beis Hillel say: Both hot water and cooked food. Beis Shammai say: We may remove [the food] but not replace [it]. But Beis Hillel say: We may even replace [it].