Ge 46:1 So Israel took his journey with all that he had, and came to Beersheba, and offered sacrifices to the God of his father Isaac.

 2 Then God spoke to Israel in the visions of the night, and said, "Jacob, Jacob!" And he said, "Here I am."

 3 So He said, "I am God, the God of your father; do not fear to go down to Egypt, for I will make of you a great nation there.

 4 "I will go down with you to Egypt, and I will also surely bring you up again; and Joseph will put his hand on your eyes."

This was to encourage Jacob and to give him assurance that everything was in accordance to God's plan and program. This would also serve to encourage Moses' original readers to leave Egypt and return back to the promise land. That their leaving Egypt was in accordance to God's plan and program for them. Their return was what God told their forefather Jacob many many years ago, as seen in these verses.