Pg 48: It is permissible to keep hot water warm on the Sabbath, but not to heat up cold water.
Pg 49: 39 Prime activities prohibited on the Sabbath, parallel to the 39 activities involved in constructing the Tabernacle.
Pg 50: A person should wash his face, hands and feet daily, in honor of God.
Summary Chapter 4: “Bameh Tomnin”: Prohibition of insulating hot food on the Sabbath. Differentiation between insulators that add heat (prohibited) and those that merely preserve heat (permitted).
Insulators that add heat are “muktzeh” and can’t be handled directly.
Allowed to insulate food or drink to keep it cold.