Jamieson, Fausset and Brown on Exodus 13:19

19. Moses took the bones of Joseph with him--in fulfilment of the oath he exacted from his brethren (Ge 50:25, 26). The remains of the other patriarchs (not noticed from their obscurity) were also carried out of Egypt (Ac 7:15, 16); and there would be no difficulty as to the means of conveyance--a few camels bearing these precious relics would give a true picture of Oriental customs, such as is still to be seen in the immense pilgrimages to Mecca.