What did God lose when Joseph was in Egypt and his brothers were in rebellion?
God lost His chosen people, the nation of Israel, His covenant people. With Joseph in Egypt and the other brothers in rebellion, He lost control of them. They therefore needed to be bought back. This redemption pattern is what Exodus teaches through the blood of the Passover lamb.
Les explains that all of Scripture consistently teaches the idea of something that was owned and then lost—or "hopped," as he puts it. Israel were God's covenant people until, because of the brothers' sin, Joseph ended up down in Egypt. While Joseph was in Egypt and the other brethren were in rebellion, God lost His chosen people and lost control of them. Therefore He would have to buy them back, and that is what the book of Exodus is about: redemption through the blood of the Passover lamb. Les then applies the same pattern to us today, because Romans 3 says all have sinned and come short of God's glory, yet sinners can be justified freely by His grace through the redemption that is in Christ Jesus.