Pesahim 75a and Pesahim 75b, what counts as fire for a range of issues–roasting the Pesah, a burn that turns into tzara’at, putting people to death by burning– and whether coals count as fire, for the Pesah and for bringing coals into the Holy of Holies as part of the Yom Kippur service. Closing with a Mishnah about when impermissible material splatters onto or into permissible.
