Genesis 46:2 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.”
God spoke through a vision. Remember Joel 2, young men will see visions & old will dream dreams? Again, God is able to reveal to anyone anyway He wants. I think the LORD is rekindling his faith, reminding him that this voice he hears is that from the God who called him long ago, in his younger days. How refreshing to see a vision from the LORD. Jacob would need this guidance from God in order to take his whole family to Egypt. Truth is, we need to hear the LORDS voice on every move we make in this life. We are not to commit to anything without the LORD giving us orders & providing us His peace.