One of the most enigmatic of all ancient Jewish religious customs was the use of ashes of a red heifer to purify people and objects defiled by a corpse. The ashes were combined with spring water and other ingredients in a vessel to produce a mixture called “water of lustration”, which was sprinkled on the impure objects or people. We discuss four questions concerning the use of the ashes of the red heifer: (I) Why a cow? (II) Why red? (III) Why ashes? (IV) Was it an original Jewish innovation, or like various other aspects of the Jewish religion, the modification of an earlier pagan rite? We propose that this Jewish rite resembles an ancient Egyptian rite in which red-haired men or cattle were scarified and burnt and their ashes scattered with winnowing fans. We argue that the Jewish red heifer ash ritual may have originated in surrounding pagan cultures reflecting the transition from pantheism to monotheism.