Adam Clarke's Bible Commentary Verse 3. Forty days] The body it appears required this number of days to complete the process of embalming; afterwards it lay in natron thirty days more, making in the whole seventy days, according to the preceding accounts, during which the mourning was continued.
Matthew Henry Commentary
Verses 1-6 - Though pious relatives and friends have lived to a good old age, and we are confident they are gone to glory, yet we may regret our own loss and pay respect to their memory by lamenting them. Grace does no destroy, but it purifies, moderates, and regulates natural affection The departed soul is out of the reach of any tokens of our affection but it is proper to show respect to the body, of which we look for glorious and joyful resurrection, whatever may become of its remains in this world. Thus Joseph showed his faith in God, and love to his father. He ordered the body to be embalmed, or wrapped up with spices to preserve it. See how vile our bodies are, when the soul has forsake them; they will in a very little time become noisome, and offensive.
Original Hebrew וימלאו4390 לו ארבעים705 יום3117 כי3588 כן3651 ימלאו4390 ימי3117 החנטים2590 ויבכו1058 אתו853 מצרים4713 שׁבעים7657 יום׃3117