In Chapter 2, the members of Park Street Church in Boston (founded 1809) wrestle with the question of how to maintain their church’s historic identity without becoming a museum. The solution is an organic interpretation of progress. Park Street leaders believe that, just as a seed contains all the genetic information necessary to become a mature plant, healthy change unfold slowly and logically, according to a predictable trajectory, from a single point of origin. This chapter analyzes how the congregation’s understanding of progress is reflected in its preaching and musical repertoire. Just as God’s covenant with Abraham unites Israel and the New Testament church into a single people of God, so too does a musical “covenant” penned in 1810 by the church’s first musicians unite nineteenth- and twenty-first century congregations into a single Park Street Church.