Thank you for the question on the enslaved Jews deliverance from Egypt, “Why did the Hebrew god take so long to save his people from Egyptian enslavement?”
I would like to suggest for one’s consideration the reasons why God declared that the descendants will enslaved 400 years. Read Exodus 15.
A. The reason for the 400 years in Egypt is so that the population of the descendants of Abraham will become an army that can conquer the Promise Land.
When Jacob took his family into Egypt, they were numbered 70. If they stay as a small tribal group, they would not be a military force to be reckon with in the Promised Land. If they remained as people group being 500 even to 1000, that will not be a significant force to defeat the Canaanites in the land. Time was needed for the descendants of Abraham to multiply.
B. The reason for the 400 years in Egypt is so that the enslaved descendants of Abraham will know the difference between the rulership of Pharaoh and of the God of Israel.
Pharaoh enslave them even attempted to kill the males of Abraham’s descendants. They were not a free people but an enslaved people with little or no rights at all. They had experienced the cruelty by Pharaoh but not they will experience the grace and power of God. The 400 years or a good portion of that time gave the people a contrasting lifestyle either under Pharaoh or the God who delivered them and made them his own possession and a priesthood.
C. The reason for the 400 years was to allow the Canaanites to fully express their sinfulness.
God gave the Canaanites 400 years to change their attitude and conduct in the land. They had not changed and even became worse as with child sacrifice. God gave the Canaanites time to repent of their wicked ways before pronouncing judgment on them.
D. The reason for the 400 years was to show Pharaoh and the Egyptians that there is only one true God, the LORD (YHWH).
Pharaoh was at the height of his power with riches untold. The gods/goddesses of Egypt were viewed as the most powerful deity through their conquest of other neighboring countries. The Israelites saw what Pharaoh could do and their gods. The 400 years of a distant belief of a Creator God was challenged by the gods of Egypt. The 400 years was to prove that the gods of Egypt were nothing and without an army, the God of Israel was able to devastating plagues upon the land and upon the people. The gods of Egypt could not defeat the God of Israel.
E. The reason for the 400 years was to show Abraham descendants that the Creator God keeps his word.
It is unclear whether Abraham told Jacob and Jacob to his children that they would be in Egypt for 400 years. When Joseph died, he asked that he be not buried in Egypt and that his body be taken to the Promised Land. It appears at least that Joseph knew and those who saw the tomb of Joseph was reminded of the words spoken by God to Abraham.
SUMMARY: The 400 years was to fulfill the prophesy given by God and to allow the descendants of Abraham to become an armed force to be reckon with in conquering the Promised Land.
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