What did God command the patriarchs about leaving the Promised Land?
God commanded Abraham, Isaac, and Jacob not to leave the land of promise. To Isaac specifically He said to sojourn in that land, adding the promise, "I will bless you." The patriarchs knew this directive, so leaving the Promised Land conflicted with God's instruction.
Les explains that God had been telling Abraham, Isaac, and Jacob not to leave the land of promise. He points back to chapter 26, where God told Isaac, "Sojourn in this land, and I will bless you." The patriarchs knew that instruction. This background matters because Joseph had Pharaoh's permission to bring Jacob's whole family down to Egypt, into the best part of Egypt, Goshen. Yet God's directive to the patriarchs was to stay in the land of promise.