To Know Jesus is to Know the God of Love
The epistles of John reflect the language and style of the gospel of John. Writing in old age and serving as an overseer of house churches in Ephesus, John address a specific crisis. Apparently, some members have left the church and denied Jesus as Messiah (1 Jn 2:18-23; 4:1-3). They even stirred hostility among those who remained in the church. Thus, the letters provide a window to the challenges that John faced in those churches.
1 John serves as a prescription to the crisis, while 2 and 3 John focus on the particulars. Nonetheless, these letters were written to assure believers, who remained with the church that God is still with them. John does so by focusing on repeated themes about life, truth, and love in knowing Jesus Christ.