(Deuteronomy 11:31)
When the Lord called Israel out of Egypt, He used Moses and Aaron his brother to lead the people to their Promised Land –Canaan. They were then a multitude of people that over the years grew from seventy when they first arrived in Egypt to over a million in the period of over 400 years. That happened according to the word of the Lord to Abraham when confirming His covenant: He said, know positively that your descendants will be strangers dwelling as temporary residents in a land that is not theirs, and they will be slaves there and will be afflicted and oppressed for 400 years… On the fourth generation, they shall come back here [to Canaan] again, for the iniquity of the Amorites is not yet full and complete (Gen. 15:13, 16). In the span of time of 400 years Israel suffered as slaves in the land of Egypt, after Joseph had died and new Pharaohs came to power who did not know anything about him and his family. God heard their cry and used Moses to lead them back to Canaan, a journey that might have lasted only eleven days, took forty years.
Light from the Word 