David Wilkerson emphasizes the necessity of sharing in God's grief over sin to fully experience His joy. He illustrates this through biblical examples, such as Noah, David, Amos, Nehemiah, and Paul, who all grieved for the transgressions of God's people. Wilkerson calls for a new generation of believers, the 'Samuel Company,' who are sensitive to God's heart and willing to confront sin within the church. He warns against the complacency of modern ministers who prioritize comfort over holiness, urging them to embrace the grief of God as a pathway to true joy. Ultimately, he concludes that those who mourn for sin will find profound joy in their relationship with Jehovah.