Charles Finney delivers a powerful sermon titled 'Moral Insanity,' emphasizing that the unconverted heart is inherently evil and mad, leading individuals to act against their own best interests. He explains that moral insanity is a deliberate choice to reject God's truth and pursue sin, despite knowing better, which results in a state of rebellion against divine authority. Finney illustrates this madness through various examples, showing how sinners prioritize temporal pleasures over eternal truths, ultimately leading to their own destruction. He warns that this moral insanity is a grave condition that can only be remedied through genuine conversion to God, restoring the will to align with reason and conscience. The sermon concludes with a call to recognize the seriousness of moral insanity and the importance of not quenching the Spirit's work in our lives.