Genesis 50:3

Forty days. It is known from Egyptian documents that the length of the period from the death of a man to his burial varied. In one case the embalming occupied 16 days, the bandaging 35 days, and the burial 70 days, 121 days in all. In another case the embalming occupied 66 days, preparations for burial 4 days, and the burial itself 26 days, in all 96 days. Elsewhere we are told that the embalming lasted for 70 or 80 days, and the burial 10 months (see E. A. W. Budge, The Mummy). The time involved depended upon the wealth of the family of the deceased and the period of Egyptian history. Jacob, being the father of the prime minister, received the best care of the time. His embalming continued for 40 days, and the preparations for his burial another 70 days. This was proclaimed an official period of mourning.