González clarifies the nature and method of Wesley's theology, which Albert Outler famously christened the Quadrilateral, and he suggests that, while helpful, to be more descriptive of Wesley's intent and the spirit of the Reformation to Scripture, reason, tradition, and experience, we must add mission.

While many might believe that the phrase "reformed but still reforming" has been co-opted by modern-day Calvinists, these words also ring true for Wesleyans. Looking to John Wesley, this book takes the long view of the relationship between the elements of the Quadrilateral and mission, thus finding new, common ground upon which theological liberals and conservatives might stand together. The book says that the addition of mission to the Quadrilateral can also help the church move beyond the bifurcation of social justice and holiness, and that the people called Methodists must hold on to both or risk the success of their witness, mission, and ministry.