Rabbi Levi observed: A slave buys, the son of a bondmaid sells, and a freeborn son becomes slave to both.
In the narrative unfolding of the biblical drama, the Joseph story accounts for the arrival of Jacob's sons and their descendants in Egypt. It also serves to introduce one of the main themes to emerge from the rest of the biblical story: the overturning of oppression with redemption.
As Rabbi Levi notes, Potiphar—who purchases Joseph in Genesis 39:1—was himself a slave of Pharaoh, but was empowered to purchase another slave. "The son of a bondmaid" refers to the caravan of Ishmaelites, the tribal descendants of Hagar, who purchase Joseph from his brothers (Gen. 37:25). Joseph, born free, becomes a slave to both in turn—and ultimately brings the story of oppression and redemption to a climax in Genesis.
The overturning of roles in this parashah is a prelude to the ultimate message of the Bible: hope. As Americans, we are comfortable with the worldview that Rabbi Levi observed in the parashah, the idea that even the most minor of players on the human stage is not trapped by the story of his or her birth. We, like Joseph, Potiphar, and the Ishmaelites, have roles to play beyond what might be expected from us given our "station in life." Slaves will one day be free, and the uplift of the Joseph story is that although he became a slave for a time, he and his descendents were one day brought from freedom to redemption.