There are three major gaps in the Bible in terms of what was happening. This is the second. The first was before the Flood, when we skip, in Genesis 4, from the murder of Abel to the murders by Lamech, generations later. The last major gap is the one between the Old and New Testaments. This gap is 400 +/- years long. Once Joseph was dead, interest in the Israelites ceased and there is no chronicle of their lives. All we know is what Exodus 1:7 tells us, "but the Israelites were fruitful and mulitiplied greatly and became exceedinly numerous, so that the land was filled with them." We will see later that several million left Egypt with Moses. And yet only Jacob and 70 descendants had started, approximately 400 years earlier. I don't know how to do the math for this sort of thing, but I can see we are talking about a MAJOR population explosion! In the meantime, there has been a change of Egyptian rulers, and probably not just rulers, but probably entire dynasties, for the new king, or pharaoh, "did not know about Joseph." Since Joseph had saved the entire populace from starvation and set up the entire economic system for the country in the process, it is highly unlikely that anyone in the same dynasty as the Pharaoh Joseph served under would not know the incredible history involving this man and his people. So, given this combination -- an exploding Israeli population and a new king/Pharaoh that did not know about these people, you have a situation ripe for panic. And, basically, that is what happened. The Israelites were quickly enslaved by one means or another. And yet God continued to bless this strange people and their population kept growing. But the more of them there were, the more the Egyptians were nervous and treated them harshly as slaves. Finally the Pharaoh decides he has got to stop this population boom where it starts -- with all these healthy babies! Pharaoh commands that the midwives kill the baby boys, but allow the girls to live. The midwives quietly refuse, fearing God more than man. God blesses them, giving them families of thier own, and Pharaoh gets more and more upset, until he finally issues the command that all baby boys are to be drowned in the Nile. The girls, again, will be allowed to live. Just as a side note here, there were times when the Nile was considered a deity in itself -- was this throwing of the baby boys into the Nile something that was done supposedly to honor this deity? Is this how the Pharaoh got away with such a cruel order? Were the Egyptians honestly that callous? The Bible does not always give us all the details we would like, but that is the best. If we had more details we would be far more tempted to judge the various people in these histories. But that is not what they are for. They are to demonstrate God, not man. Getting back to Exodus, it is at this point, when all the baby boys are ordered thrown into the Nile, that Moses is born. These are precarious times, and the mothers must have been going between heartbroken and furious. Both fear and anger would have been building to intolerable levels.