The Promise: Passed On or Not?

This week, we learned about the Brit Bein Habetarim. After Avraham had helped the four kings win the war against the five kings, he had concerns about the validity of the promise. Therefore, Hashem had to restate and authenticate the promise. G-d started by reassuring Avraham that he would have children of his own to inherit the land from him. After this, Avraham cut up animals and walked between them. As we discussed in class, this was the handshake of the time and was not considered odd at the time. G-d then continues by telling Avraham that he would live a life of peace and prosperity. His children, starting in four generations, would be strangers in a strange land and would be afflicted for four hundred years. At the end of these four hundred years, they will be redeemed from bondage and THEY will be the ones to inherit the land from Egypt to the Euphrates.

I have a problem with this story. We know now that the four generations after Avraham starts with Yosef's children, who were born in Egypt. Yosef was the firstborn son of Yaakov and Rachel. He was Yaakov's "favorite" son and was educated by Yaakov himself. As we learned in class, Avraham's duty was to spread ethical monotheism and act accordingly. I wonder if he passed down the knowledge of what he was promised at the Brit Bein Habetarim to his son Yitzchak. If he passed it in to Yitzchak, did he pass it on to Yaakov? If it was passed on to Yaakov, did he tell Yosef? Finally, did Yosef tell his sons what would happen to them and their descendants?

We all know Yosef's story. His brothers were jealous of their father's clear display of favoritism towards Yosef. They threw him in a pit and sold him as a slave to Egyptian merchants. In Egypt, he became a slave in the house of Potifar, an officer of Pharaoh. He rose up in the ranks, but was thrown in jail. Pharaoh had troubling dreams and Yosef was the only one who could interpret them. He was then released and became Pharaoh's second in command in Egypt. He helped save Egypt from a great famine and his brothers eventually went down to Egypt in search of food. There, Yosef revealed himself to them and the entire family goes down to Egypt.

My question is: did Yosef have any idea what he and his brothers had started when they sent him to Egypt? Egypt was the land of the bondage of the descendants of Avraham and because of Yosef's success there, the entire family left Canaan and went to the land where they would be slaves fro four hundred years. I wonder what was running through Yosef's mind when he was sitting in the pit. Was it fear for the present or fear for the the future?