Why did the teacher spend so much time on the Abrahamic covenant?
So much time was spent on the Abrahamic covenant because all of Scripture rests on that covenant God made with Abraham. God established it to give Abraham's descendants, the nation of Israel, the land of Canaan, and He never forgets His covenant promises to Abraham, Isaac, and Israel.
Les explains that he spent so much time on the Abrahamic covenant because all of Scripture is going to rest on that covenant God made with Abraham. He points out that God again comes back to it in Exodus 6, where He says He has established His covenant to give the children of the covenant, the children of Abraham, the nation of Israel, the land of Canaan, the land of their pilgrimage wherein they were strangers. Les emphasizes that God heard the groaning of the children of Israel in Egyptian bondage and remembered His covenant, and God will never forget it. He warns against the idea that God is all through with the Jew, affirming that God still has His covenants uppermost with regard to the nation of Israel. Then in verse 6, Les notes God says, 'I am'—Jehovah—and promises to bring Israel out from under Egyptian burdens, rid them of bondage, and redeem them, buying them back and paying the price to set them free. He connects this to the book of redemption and notes that Paul and other writers of Scripture also speak of our redemption.