How long did the Israelites suffer abject slavery in Egypt?
The abject slavery in Egypt lasted about 140 to 150 years, not the entire 400-year period. It was not even 200 years, according to the biblical timeline. The full 430 years spans from Abraham's call until Israel's exodus, with the harshest bondage occupying only a portion near the end.
Les explains that from Joseph's death and the birth of Moses, the timeline reaches the 215-year mark, which is exactly halfway in the 430 years God mandated from the call of Abraham until Israel would leave Egypt. Therefore, the abject slavery was not the whole 400 years. It wasn't even 200 years. It was more like 140 or 150 years.