You must not follow the practices of the land of Egypt, where you used to live, and you must not follow the practices of the land of Canaan, into which I am bringing you. You must not walk in their customs.
After divers ceremonial institutions, God here returns to the enforcement of moral precepts. The former are still of use to us as types, the latter still binding as laws. We have here, 1. The sacred authority by which these laws are enacted: I am the Lord your God (Lev 18:1, Lev 18:4, Lev 18:30), and I am the Lord, Lev 18:5, Lev 18:6, Lev 18:21.
Commenting on Leviticus 18:1-5
After the doings of the land of Egypt, wherein ye dwelt, shall ye not do,.... Where they had dwelt many years, and were just come out from thence, and where they had learned many of their evil practices; not only their idolatrous ones referred to in the preceding chapter, which it is certain they followed, Eze 20:7; but also their immoral practices, particularly respecting incestuous...
After the doings of the land of Egypt, wherein ye dwelt, shall ye not do: and after the doings of the land of Canaan, whither I bring you, shall ye not do: neither shall ye walk in their ordinances. (a) You shall preserve yourselves from these abominations following, which the Egyptians and Canaanites use.