The central message of this sermon is that Christians must maintain a balance between doctrine and life, avoiding foolish controversies that displace the central truths of the gospel while also being careful to identify and defend essential doctrines. The teacher argues that when Christianity is presented as "Christianity and" something else - such as vegetarianism or faith healing - it elevates human additions above the core teachings of scripture, leading to a displacement of the gospel. In contrast, the teacher emphasizes the importance of focusing on essential doctrines that are foundational to the Christian faith, such as the doctrine of the atonement and salvation by faith. By distinguishing between essential doctrines and disputable matters, Christians can avoid unnecessary controversy and focus on living out their faith in practical ways. The takeaway is that a biblical balance between doctrine and life is crucial for maintaining a healthy and vibrant faith community.