Why did Joseph want his bones dug up and buried in the Promised Land?
Joseph prophesied that Israel would not remain in Egypt. To demonstrate his confidence in God's promise, Joseph insisted that when they left, they would take his bones and bury them in Canaan -- a land they would not possess until 400 years later. "Then Joseph made the sons of Israel swear, saying, "God will surely take care of you, and you shall carry my bones up from here"" (Genesis 50:25). The children of Israel fulfilled that request (Exodus 13:19; Joshua 24:32). The fact that they kept track of Joseph's remains for so long shows they believed the promise. The Hebrew writer cites this as evidence of the strength of Joseph's faith. "By faith Joseph, when he was dying, made mention of the departure of the children of Israel, and gave instructions concerning his bones" (Hebrews 11:22).
It would not mean they had to dig up Joseph's body. Joseph was mummified, as Jacob was done earlier, and placed in a tomb. "So Joseph died at the age of one hundred and ten years; and he was embalmed and placed in a coffin in Egypt" (Genesis 50:26). The crypt would have been opened and the box with Joseph's remains would have been taken to Canaan.