The Midrash Rabba says in the beginning of the Book of Shemos (Exodus) that Abraham did not
rebuke his son Ishmael, and Ishmael went into evil ways, and Abraham hated him. This is shown by
the fact that Abraham sent Ishmael away without money even though Abraham was wealthy. Isaac
did not rebuke his son Esau, and eventually did not give the birthright to Esau. David did not
rebuke his son Abshalom, and Abshalom eventually pursued his father trying to kill him. The Midrash
teaches that G-d loved the Jewish people so He caused them to be slaves, a way of rebuking them
so that they would grow into a nation worthy of receiving the Torah.