In verse 1, we see how God regarded Israel. Moses wrote Deuteronomy at the end of Israel's wandering in the wilderness, forty years after their release from Egypt. After spending many generations under Egyptian rule, the Israelites had absorbed certain aspects of Egyptian culture as their own, and many of these were wrong.
Idol worship, which the Israelites quickly returned to with the Golden Calf (Exodus 32:4), was just one of the wrongs that God needed to fix. He speaks here of not mutilating the body or shaving the head for the dead. The Bible does not clearly explain if the Egyptians practiced cutting themselves or shaving their heads for the dead, but many pagan peoples have done so as a sign of mourning or piety or to attract the attention of their god. God addresses it in a number of places (Leviticus 19:28; 21:5; I Kings 18:28).
