Thomas Reade emphasizes the critical need to understand the two fundamental sources: the source of human misery, which is sin, and the source of divine mercy, which is found in Christ. He argues that human wisdom has failed to uncover these truths, and only the Bible reveals the origin of sin and the redemptive grace of God. Reade highlights that through Adam's sin, death entered the world, while God's mercy is manifested through Jesus Christ, who reconciles humanity to Himself. He calls for a deep understanding of Scripture to grasp the nature of sin and the operations of God's love, urging believers to recognize their need for salvation and the grace offered through Christ. The sermon concludes with a heartfelt prayer for enlightenment and a desire to live in the light of God's mercy.