Editing Masekhet Shabbos (section)

== Pouring Hot Water into Cold ==
Pouring hot water into cold water is a halachic question regarding whether it is permitted to pour hot water into cold water in a way that causes the cold water to become boiling through the mixing. This is discussed in the books of the Tzemach Tzedek regarding pouring hot water onto cold tea remnants.

The source of the doubt is in the words of the Mishnah:<blockquote>"If one removed a kettle (from the fire), one may not put cold water into it to heat it, but one may put (cold water) into it or into a cup to make it lukewarm." — Shabbat Chapter 3, 5</blockquote>The Gemara (42a) further states: "Our Rabbis taught: One may put hot water into cold water but not cold water into hot water - these are the words of Beis Shammai. But Beis Hillel say: Whether hot into cold or cold into hot is permitted. When is this said? In a cup, but in a bathtub - hot into cold but not cold into hot. And Rabbi Shimon ben Menasia forbids."