The three great Patriarchs of Judaism are also celebrated as saints by the Catholic Church on this day. It was their perseverance and devotion to the one, true God that made it possible to establish the Chosen People from whom the Savior of the world would be born.
Very roughly around 2000 B.C. (give or take a century or two!) Abraham left Ur in Mesopotamia and responded to an invitation from God to enter into a covenantal relationship with him. His son Isaac followed the faith of his father, and his son, Jacob, did the same. Jacob would eventually be renamed Israel, and the entire nation of people descended from him would come to be known collectively by the same name.
Since Jesus Christ is descended from these Patriarchs, all of us who have been baptized have entered into a familial relationship with Abraham, Isaac, and Jacob. They are our spiritual forebears. It is fitting, therefore, that we pray for their intercession, and we can be conscious of their presence in heaven in a special way whenever we sing, “O Come, O come Emmanuel, and ransom captive Israel…”