T. Austin-Sparks emphasizes the purpose of John's First Letter, which was to confirm the faith of believers amidst confusion and division in the early Church. He highlights the challenges faced by Christians due to various teachings and the infiltration of worldly influences, leading to uncertainty about the truth. John, untouched by these conditions, repeatedly asserts 'We know' and 'This is' to affirm the certainty of faith and the fundamental truths of Christianity. The sermon underscores the significance of 'Light,' 'Life,' and 'Love' as essential elements for believers to navigate their faith in a chaotic world. Ultimately, Sparks calls for believers to actively walk in the Light, which brings clarity and fellowship among Christians.