The ancient Egyptians believed that people could not enjoy the afterlife unless their bodies were well-preserved. Only then could their souls recognize their bodies and return to them. The elaborate process of mummification was developed to ensure this preservation.
"May you ignore my wrong-doing and may you set me as the one honored with the spirits; may you protect my soul in the Sacred Land, may it navigate in the Field of Rushes, because I have passed on in joy." Spell 15 - The Book of the Dead