What was God's purpose for the Jews going down to Egypt?
God's purpose was earthly and sovereign: Israel had to go into Egypt, multiply into a great nation, endure slavery, and be ready to leave under Moses after about 215 years. They would emerge as five to seven million, more numerous than any other Middle Eastern nation, fulfilling Abraham's promise.
Les explains that God was remembering His promise to Abraham that his offspring would be as numerous as the pebbles of sand. In Egypt God would make them a great nation. This was an earthly promise, not a heavenly one, because Israel is an earthly people with earthly promises. They had to go down to Egypt where Joseph had food aplenty, then into slavery, and be ready to come out when Moses led them. God's eternal purpose included a population explosion: they would come out about 215 years later, five, six, or seven million strong, more numerous than any other single tribe or nation in the Middle East. Les emphasizes that all Israel's covenant promises are earthly, looking to an earthly Kingdom with Messiah as King, not heaven.
And he said, I am God, the God of thy father: fear not to go down into Egypt; for I will there make of thee a great nation:
More Questions
What did God tell Jacob when he was about to go down to Egypt?
God spoke to Jacob and told him not to fear going down into Egypt, because there God would make of him a great nation.
Why did God forbid Isaac from going to Egypt but tell Jacob to go there?
God had told Isaac not to go down into Egypt but to sojourn in the land of promise, yet He now tells Jacob to go down into Egypt, which is a change.