T. Austin-Sparks emphasizes the profound significance of hearing the voice of the Son of God, as illustrated through the story of Lazarus. He explains that true spiritual hearing transcends mere physical ability and is a sovereign act of God that brings about a living relationship with Christ. The sermon highlights that only those who are spiritually 'dead' can truly hear this voice, leading to a transformative faith that redefines existence and purpose. Sparks warns against superficial Christianity, urging believers to seek a deeper, experiential knowledge of Christ that is rooted in divine revelation rather than human persuasion. Ultimately, he calls for a recognition of the eternal implications of hearing God's voice, which brings life and hope even in the face of despair.