The central message of this sermon is that the church must maintain its purity and exclude sin from within, as sin will inevitably permeate and corrupt the entire community. This principle is rooted in God's absolute standard of holiness and perfection, which cannot tolerate even the slightest bit of sin. The sermon argues that, despite appearances to the contrary, the New Testament's approach to dealing with sin is not a departure from God's standards, but rather an expression of His love and mercy, as seen in the contrast between the Old Testament's literal stoning of sinners and the New Testament's practice of delivering sinners to Satan for their own destruction. The sermon also emphasizes that true salvation is through faith alone, not by our ability to keep God's commandments, which we inevitably fail to do in our hearts, no matter how well we may externally obey them. Ultimately, the church must recognize its need for Christ's redemption and take steps to exclude sin from within its midst, lest it become like a community with "a camel's nose" of sin that will eventually allow the entire camel into the tent.