Acts 7:11 - 15

"'Then a famine struck all Egypt and Canaan, bringing great suffering, and our fathers could not find food. When Jacob heard that there was grain in Egypt, he sent our fathers on their first visit. On their second visit, Joseph told his brothers who he was, and Pharaoh learned about Joseph's family. After this, Joseph sent for his father Jacob and his whole family, seventy-five in all. Then Jacob went down to Egypt, where he and our fathers died.'" NIV translation

Stephen is still recalling Jewish history as he speaks to the Sanhedrin. Here, he is reminding them about how God used one of his people to save them all from starving. In spite of his brothers selling him into slavery, Joseph was where God wanted him to be at just the right time to be used to save his people. The same is true of us and Jesus Christ. 

Both Jesus and Joseph were obedient even when it was difficult and because of that God was able to use them to save his chosen people.

Acts 7:16 - 19

"'Their bodies were brought back to Shechem and placed in the tomb that Abraham had bought from the sons of Hamor at Shechem for a certain sum of money. As the time drew near for God to fulfill his promise to Abraham, the number of our people in Egypt greatly increased. Then another King, who knew nothing about Joseph, became ruler of Egypt. He dealt treacherously with our people and oppressed our forefathers by forcing them to throw out their newborn babies so that they would die.'" NIV translation

Stephen is reminding the members of the Sanhedrin about the history of Israel. He is reminding them what reliance on their ancestor had brought the people. You see, in Egypt at the time that Stephen is describing, the Israelite people had become used to the favor granted them by the ruler because of Joseph. But, when the ruler was replaced, their favor was removed and they were enslaved. In a way, that is happening in the church today. People are attending services because their ancestors did and hoping for favor with God because of that. We know that, in the end, the relationship with God through Jesus Christ is what saves us and not whether our ancestors had a right relationship with God.