1 John taught me that we are liars if we say we love Christ, but hate our brothers. We must love each other as God loves us. God is Love, Light, Life.
2 John taught me to walk in the truth (The Word) and to love one another.
3 John taught me about the 3 personalities: Gaius-spread the gospel, Diotrephes-personal attention, Demetrius-adorning the gospel.