The sermon critiques Enlightenment rationalism for rejecting God, which leads to nihilism and subjective truth. It argues that Christ serves as the hermeneutical watershed, meaning all Scripture must be interpreted through His person and work. Without this Christocentric lens, readers risk falling into legalism or traditionalism rather than grasping salvation by grace. The speaker emphasizes that the Old Testament testifies of Jesus and cannot be understood apart from Him. Proper biblical interpretation requires a covenantal framework anchored in Christ to avoid theological error.