This is a different man than left his parents some 20-odd years before. He now clearly saw the vision of a family that he was to become. He knew it was his responsibility to protect the family and obey God. He divided the group into two bands so that if Esau wanted vengeance, he was going to sacrifice himself for his family, so the family would still be safe. He was willing to sacrifice himself for the rest of the family because he knew God's promise would happen and he was doing what he had to do to get it done.
And now in all humility he tells God he knows what he has been, and what he is, and that he is the least of God's people, unworthy of God's mercies. He is not worthy of having a glimpse of the truth of the Family of God and his part in it, but he has grabbed on to that vision. He will not let go. He reminds God of the promise that He made of his descendants being as the sand of the sea, and he will do his part because he knows that God is moving forward, and He will do His.
