People reject the gospel of Christ because of their unbelief and hardened heart. In this sermon on Acts 4:8–10 titled “The Tragedy of Unbelief,” Dr. Martyn Lloyd-Jones explains that this is the universal problem. Sinful people have always rejected the message of the gospel and those that bring the message, as was the case with the apostles. They were persecuted, some to death, and they suffered because they refused to be silent. This persecution and rejection of the gospel has been present throughout church history. Lloyd-Jones says that the tragedy of this rejection of the gospel is that when people reject the gospel, they lose any hope of salvation. Apart from the gospel that is persecuted and hated, no one can be saved. There is no peace, hope, or joy without the redeeming power of the gospel of God. Ancient and modern humanity are no different for their foolish and blind unbelief. Apart from the light of God’s grace in Christ, both are lost and live in darkness. The root of this is sin, but in their darkest sorrows, people reject the only hope that the world has ever known. This rejection of the message of salvation is the great tragedy of unbelief and the very remedy to the world’s greatest problems is what the world despises the most.

http://www.mljtrust.org/sermons/the-tragedy-of-unbelief/