1, 2, and 3 John are all written to first-century believers who were ransacked by apostasy. John writes from the heart of a pastor, giving these believers ways to recognize false believers while leading them to assurance of their own salvation. In addition, he exhorts them how to interact with those who deny the faith.
In each letter, John also stresses the same application – walk in the truth and love one another. Love and obedience are so central to John’s letters that these two characteristics are used to reveal whether an individual truly as eternal life or not.
Finally, the cord of hope winds through each epistle. This hope is found only in the person and work of Jesus Christ. Despite the difficulties of apostasy and false teaching, John’s audience has every reason to have hope because Jesus has defeated Satan, the light has overcome the darkness, and faith overcomes the world!
The theme of Christ’s triumph is something the Apostle John stresses in all his writings, including the Gospel of John and the book of Revelation. Perhaps this inspired insight is what kept John from a depressed countenance and gave him a positive outlook. To be sure, John recognizes – as we should – the despair of apostasy and difficulty, but he does not let these things sway him from the hopeful expectation of the future triumph of Christ. It is precisely this triumph that serves as the grounds of why we love one another, why we walk in truth, and why we have hope and assurance in the midst of trials.