What we call "heat" is actually a form of energy produced from the movement of atoms and molecules. When we feel ourselves getting hot, that is usually because we are being bombarded by fast-moving particles in our environment. Cold, on the other hand, is caused by a slowing of atomic movement.

This understanding, that heat is produced by the rapid movement of atoms, is one of the achievements of physics in the 19th century. This discovery links the microscopic world of the atom to the macroscopic world that we can see and feel with our senses.

On a human level as well, the concept of heat denotes movement, action. When we are “heated up” about a cause or an idea, that means we are active and generating energy. “Cold,” on the other hand, indicates indifference or passivity. In spiritual terms, warmth is associated with faith while coldness is associated with skepticism and doubt. Performing mitzvot in a cold manner indicates lack of enthusiasm and conviction; action by rote, out of habit.

Regarding G-d, a verse in Torah states, “For the L-rd your G-d is an all-consuming fire.” Judaism is a movement that requires action and passionate activity. It is not a moribund culture or tradition, consisting of a country club masquerading as a synagogue. Judaism demands constant input and focused activity, to transform the world by bringing holiness to it. Ever since Abraham first appeared on the world scene in Babylonia, Judaism has been a source of transformative ideas that shaped world culture and ethics.