It would be difficult to imagine the resurrected Lord not mentioning Abraham or the covenant God made with him in His "Unrecorded Emmaus Road Sermon".  He very likely taught His two despondent disciples how the promises, blessings, and fulfillment of that covenant center on Himself (although His identity was not yet revealed to the two).  The Lord's initial call to Abram of Ur of the Chaldees (a Gentile!) was analogous in importance to the divine summons to Moses at the burning bush and to Saul on the Damascus Road.  It was a call of grace for the entire world, for the message of salvation is at the heart of that unconditional covenant, and the world's Saviour (and written Word of God) was to come from Abraham's loins!

For a solid understanding of the Abrahamic Covenant, this is a "must listen" message.