The central message of this sermon is that unbelief has its own set of problems, which include explaining away the evidence of God's presence and power in the world. The speaker argues that those who deny the resurrection of Jesus must account for the many signs and wonders that attest to its truth, such as the Shroud of Turin, which presents a mysterious image that cannot be easily explained away. The sermon suggests that the chief priests and elders, who were instrumental in Jesus' death, are guilty of covering up the truth and silencing their own doubts through bribery and lies. This message advances the idea that faith is not just about maintaining one's own conviction in the face of doubt, but also about confronting the reality of God's presence and power in the world. The takeaway the speaker wants listeners to understand is that unbelief has its own set of consequences and that it requires a significant amount of effort and deception to ignore or deny the evidence of God's work in the world.