Some critics suggest that Genesis and Exodus are separate stories from two different sources that were combined. Here is a brief overview and exploration of the transition between Genesis and Exodus, demonstrating a smooth transition between the two.

The book of Genesis ends with a family reunion between Joseph and the other Israelites. This takes place 215 years before the Exodus event. In Galatians 3:16-17, Paul states that the period from Abraham’s covenant (at age 75) to the Exodus (when Moses was 80) spanned 430 years. Jewish historian Flavius Josephus also confirms this. Abraham was 75 when the covenant was made, and he went to Canaan. He had Isaac at 100 (25 years later). Isaac had Jacob and Esau when he was 60. Then, at 130 years old, Jacob was reunited with Joseph. 25 + 60 + 130 = 215, which is half of 430. So, from Abraham to Moses, the covenant people spent 215 years in Canaan and 215 years in Egypt.

Joseph was made vizier at 30 (Gen 41:45-57), and the famine (which started 7 years later), had only been around for 2 years (Gen 45:6). So Joseph was 39 (30+7+2) when he reunited with Jacob, meaning he was born when Jacob was 91 (130-39). Jacob had only been married for 7 years before Joseph’s birth, so his first 11 sons and Dinah were all born within those 7 years. A mother can’t conceive and give birth to more than one child in a year unless they multi-births like twins. Since none of the children are listed as twins, it seems likely that all of Leah’s children were born once each year over the 7 years, with a birth gap in the fifth year and two births in the sixth. In the 5th & 6th years, Bilhah and Zilpah got pregnant. Then in year seven, Dinah was born to Leah, and Joseph was born to Rachel. Then Benjamin was born after Joseph was sold at age 17.

A likely scenario is that Jacob was:
-85 when Reuben was born
-86 when Simon was born
-87 when Levi was born
-88 when Judah was born
-89 when Dan and Gad were born (maybe Issachar)
-90 when Naftali, Asher, and Zebulun (maybe Zebulun if not the previous year)
-91 when Dinah and Joseph were born
-around 108 or later, when Benjamin was born

Jacob died at 147, 17 years after the family reunion. Joseph would have been 56, Benjamin would have been 39 at the most, and the other brothers would have been between 57 and 62. Then Joseph dies at 110 (Gen 50:26). Benjamin would have been 93 when Joseph died, and the other brothers would have ranged from 111 to 116. In Gen 50:24, Joseph tells his brothers to bring him into the land of Canaan when the Israelites leave Egypt, and they agreed to do so. We know that at least some, if not all, of his brothers are still alive when Joseph dies. The only other brother for whom we have a death date is Levi, who died at 137 (Ex 6:16). Levi would have been around 114 years old when Joseph died, so he outlived Joseph by 23 years.

Exodus chapter 1 tells that the enslavement started after all the sons of Jacob had died. Since Levi outlived Joseph by approximately 23 years, it’s possible that he was the last one alive. In Ex 6:20, we are told that Jochebed, Moses’ mother, is the aunt of her husband Amram. She is the younger sister of Moses’ grandfather Kohath, which makes her the daughter of Levi, so the latest she could have been born is when Levi died. There are 64 years between Joseph’s death (215 – 71 = 144) and Moses’ birth (144 – 80 = 64). If Levi died 23 years after Joseph, and Jochebed was conceived or born the year he died, she would be 41(64 – 23) years old at the youngest when Moses was born. The Israelites were enslaved for between 144 and 80 years. The minimum would be starting from the year Moses was born (he was 80 at the time of the Exodus), and the maximum would be the year Joseph died (144 years before the Exodus). Since the time of their enslavement is limited to a range, it could have begun anywhere within that range, possibly around the time Levi died (121 years before the Exodus). We don’t know for sure, but this is the framework that connects everything we know about Exodus and Genesis. More on the topic of the Israelites’ time in Egypt here.

The Israelites spent 215 years in Egypt. If each Pharaoh reigned for an average of 60-80 years, then there would have been at least 3 to 5 Pharaohs. Let’s simulate a possible scenario. Imagine that the Pharaoh, whose dream was interpreted by Joseph, dies when Joseph is 60. Then, a second Pharaoh who knew and respected Joseph reigned for 70 years, 20 years after Joseph died at 110. Then this 3rd new Pharaoh, who didn’t know Joseph, enslaved the Israelites a few years after Levi died (around 23 years after Joseph died). Levi died 41 years before Moses was born, so let’s say Moses was born under this Pharaoh’s reign. Out of nationalistic fear, he decided to commit infanticide by drowning Israelite baby boys under two (Exodus 1:22). Then his daughter found Moses and decided to raise him. She unknowingly paid Moses’ mom to nurse and help raise him in early childhood. Then Pharaoh number three dies when Moses is around 19, marking the end of his 60-year reign. Then Pharaoh number four allowed Moses to work and live in his palace, but continued the harsh treatment of the Israelites. Perhaps Moses even advocated on their behalf without them knowing.

Either way, when Moses was 40 (according to Acts 7:23), he murdered an Egyptian for beating a Hebrew, was discovered, and fled Egypt as a fugitive to Midian (Ex 2:11-15). Moses stayed in Midian until he was 80 (Exodus 7:7, Acts 7:30) when God called him back and told him that everyone in Egypt who wanted him dead was dead (Ex 4:19). This would include Pharaoh number four, ending his reign at 61 years. Then the fifth Pharaoh is the one that Moses challenges in the Exodus story, who is drowned in the Red Sea (Ex 14:26-31). 

This is one of many possible explorations of how the events between Genesis and Exodus played out. The purpose was to demonstrate that these scenarios don’t have logistical problems and that there are no contradictions that would cause issues with these events unfolding as scripture presents them. Just because we don’t have all the details doesn’t mean the ones we have can’t guide us. When applying this kind of analysis to other parts of Scripture, it refutes other claims of inconsistency or contradiction within Scripture. In other words, the Bible can defend itself regarding the integrity of narratives.