Thomas Brooks emphasizes the universal corruption of human nature, asserting that even the choicest saints are not exempt from sin and uncleanness. He explains that godly men, despite their sincere repentance, may repeatedly fall into the same sins due to their inherent weaknesses and the ongoing battle against sin and temptation. Brooks highlights the struggle of the best among us, who carry the burden of corrupt flesh and blood, making them susceptible to the subtle workings of sin and the temptations of Satan.

Theodore Epp discusses the unchanging nature of the flesh, using the story of King David's sin with Bathsheba and the subsequent murder of Uriah to illustrate how even the most righteous can fall into sin. David's attempts to cover his wrongdoing reveal the depths of human depravity and the lengths to which one might go to hide their sins. Epp emphasizes that the sinful nature inherited from Adam remains unchanged in believers, highlighting the need for understanding God's grace and sovereignty in our lives. The sermon serves as a reminder that the heart is deceitful and wicked, urging believers to remain vigilant against their fleshly desires.

G. Campbell Morgan explores the nature of man through the teachings of Jesus, emphasizing that true life is sustained not by physical needs but by the Word of God. He highlights the importance of worship and service to God as the ultimate purpose of human existence, while also addressing the duality of human nature—both the ideal and the actual. Morgan discusses the significance of loving God and neighbor as the foundation of life, and the necessity of spiritual rebirth for true fulfillment. He concludes by affirming the potential for restoration through God's grace, urging believers to recognize their divine purpose and the call to live in accordance with God's will.

A.W. Tozer emphasizes the contrast between the rapidly changing external world and the unchanging nature of humanity's inner self. He reflects on how Jesus lived in a time devoid of modern conveniences and technology, yet the people of that era were just as real and complex as we are today. Tozer argues that while our surroundings and lifestyles have evolved dramatically, the fundamental aspects of human nature remain constant. This serves as a reminder that despite external changes, our inner struggles, desires, and relationships with God are timeless. Ultimately, Tozer calls for a deeper understanding of our unchanging internal selves amidst a changing world.

Art Katz reflects on the tragic fate of Nicholas Berg, emphasizing how his naïveté and idealism led him into a perilous situation in Iraq. Katz critiques Berg's belief in the inherent goodness of people and the dangers of underestimating the complexities of human nature and geopolitical realities. He draws parallels between Berg's fate and broader societal misconceptions, including the misguided optimism of political leaders like President Bush regarding democracy in the Middle East. Katz warns that such idealism, detached from the truth of human sinfulness and the realities of the world, can lead to devastating consequences. He calls for a return to the understanding of God’s truth to navigate the complexities of life and conflict.

Thomas Brooks emphasizes the inherent wickedness present in all humans, reminding us that the potential for every sin exists within our nature. He warns that if we are not as wicked as others, it is solely due to God's grace restraining our sinful inclinations. Brooks illustrates this point by recounting a man's descent into multiple sins, highlighting the danger of underestimating our own sinful nature. He urges listeners to recognize that without divine intervention, we would all succumb to our basest instincts, becoming 'incarnate devils.' Ultimately, he concludes with the powerful reminder that our identity is shaped by God's grace.

Peter Brandon addresses the profound question of what is wrong with the world, emphasizing that the root issue lies within human nature itself. He reflects on King David's sin with Bathsheba and his subsequent repentance as depicted in Psalm 51, illustrating the necessity of acknowledging our sins and seeking God's mercy. Brandon argues that societal changes alone cannot rectify the moral decay, and true transformation begins with a broken and contrite heart before God. He highlights the importance of understanding sin, conviction, and the need for genuine confession to experience true forgiveness and restoration. Ultimately, he calls for a return to God as the only remedy for the brokenness of humanity.

John Wesley preaches about the profound truth that believers possess a heavenly treasure within their fragile, earthly bodies, highlighting the paradox of human nature that embodies both greatness and baseness. He explains that while humanity was created in God's image, the fall has led to a state of corruption and weakness, making it difficult for individuals to fully realize their potential. Wesley emphasizes that this treasure, which includes faith, peace, and the love of God, is entrusted to us in our mortal vessels to demonstrate God's power and grace. He encourages believers to embrace their weaknesses, as they lead to reliance on God and ultimately result in eternal glory. The sermon concludes with a reminder that despite our earthly struggles, we are more than conquerors through Christ.

Watchman Nee discusses the nature of man as unregenerated and bound by the flesh, emphasizing that humanity is inherently filled with lust and evil thoughts due to the fall of Adam. He explains that being 'in the flesh' leads to enmity against God and ultimately results in death, as those who live according to the flesh cannot fulfill the law or please God. Nee highlights the necessity of regeneration through the Spirit, which allows believers to overcome the desires of the flesh and live according to God's will. He warns that those who remain unregenerated are debtors to the flesh and will face spiritual death. The sermon calls for a recognition of the need for transformation through Christ to escape the bondage of the flesh.

A.W. Tozer emphasizes that all people, regardless of their external differences, share a fundamental human nature that is lost and in need of salvation. He asserts that the Christian message is directed at this shared condition, highlighting that before the cross, distinctions such as age, education, and social status are irrelevant. Tozer illustrates that Christ's sacrifice was for all humanity, not for specific groups, and that the essence of human nature remains unchanged despite varying circumstances. He encourages believers to recognize this unity in humanity as they share the message of the Gospel. Ultimately, the sermon calls for a focus on the common need for redemption that transcends societal differences.

John Wesley preaches on the concept of Original Sin, emphasizing the stark contrast between the biblical view of human nature and the more flattering depictions often presented by society. He argues that all humanity is inherently sinful, as evidenced by Scripture, which states that every imagination of the thoughts of man's heart is only evil continually. Wesley asserts that this fallen state is universal and that without divine intervention, humanity remains spiritually dead and in need of redemption. He calls for a recognition of our sinful nature and the necessity of being born again through Christ to restore our relationship with God.

T. Austin-Sparks addresses the profound transformation of humanity from God's original creation to a state of spiritual disarray, emphasizing that man is not merely a sinner needing redirection but has fundamentally become a different species than intended by God. He critiques the evangelical approach that focuses on consecration of the 'old man' rather than the necessary crucifixion of the old nature, highlighting the inadequacies of relying on human abilities in spiritual matters. Sparks asserts that true salvation involves a radical change in man's constitution, requiring a union of the spirit with God, which was lost in the Fall. He explains that the essence of man as spirit, soul, and body has been disrupted, leading to a life dominated by the soul rather than the spirit. Ultimately, he calls for a return to the original divine purpose through the transformative power of Christ's death and resurrection.

A.W. Tozer reflects on the paradox of changing times and the unchanging nature of humanity, emphasizing that despite the advancements in civilization, the core of human nature remains constant. He illustrates this point by contrasting the humble circumstances of Jesus' birth with the modern world, highlighting that while technology and society evolve, the fundamental human thirst for meaning and connection persists. Tozer suggests that this unchanging thirst is most evident during Christmas, a time that reminds us of our enduring needs and the simplicity of Christ's arrival.