Genesis 50:3

Forty days. — Herodotus (ii. 86) describes the process of embalming as occupying seventy days, but he was speaking of what he saw at Thebes, whereas Memphis was the Egyptian capital in Joseph’s time; and the mummies of Thebes are, we are told, far more perfectly preserved than those of Memphis. Diodorus agrees very nearly with the periods mentioned here, saying (i. 91) that the embalming took somewhat more than thirty days, and the mourning for a king seventy-two. The usual period of mourning among the Israelites was thirty days (Numbers 20:29 : Deuteronomy 34:8). Probably, therefore, the forty days spent in the embalming were included in the “threescore and ten days,” during which the Egyptians mourned for Jacob.