Eventually, all of Jacob/Israel’s sons died, but their descendants multiplied and grew strong and after a while they were all over the place. A new king came into power in Egypt and he didn’t know Joseph or that everyone was supposed to love the Israelites. The king decided there were just too many of those damned Hebrews and he was afraid they’d someday rise against him or start a war or something. He tried to oppress them, thinking this was the best way to avoid catastrophe (he wasn’t very bright), but the Israelites just kept on multiplying.
The king went to two midwives, Shiprah and Puah, and told them to kill any sons the Hebrews might have, but to let the daughters live. The midwives said okay, but couldn’t do it because they knew God wouldn’t like it. They told the king the Hebrew women were strong and gave birth before a midwife could even get to them. The Pharaoh told all his people to make the Israelites their slaves and to throw Hebrew boys in the Nile.