In this sermon titled "Three Keys to Church Unity," based on Ephesians 4:1-3, David Forsyth discusses the vital role of unity in maximizing the effectiveness of the Great Commission within the church. He outlines three critical elements necessary for fostering this unity: recognizing that unity is created through the gospel, cultivating it through loving tolerance, and maintaining it through diligent effort. Emphasizing the importance of these principles, he illustrates how they can strengthen the church's mission and counteract the divisive forces threatening its spiritual harmony.