The Phos Hilaron is one of the oldest hymns we know. As lamps were lit at evening, the early Christians would sing: “O gracious light, pure brightness of the everliving Father in heaven, O Jesus Christ, holy and blessed! Now as we come to the setting of the sun, and our eyes behold the vesper light, we sing your praises, O God: Father, Son, and Holy Spirit.” John says that as believers, we need to walk in the light and not in the darkness. This is a helpful way to think about the two spiritual realms or kingdoms: Darkness is known for its lies, death, spiritual blindness, and evil, while light is marked by truth, life, spiritual vision, and righteousness. These distinctions will always be true! Truth is never accompanied by death but always by life. Lies are never accompanied by spiritual vision but always by spiritual blindness. Similarly, love and obedience always go together. The command to love is both old and new (vv. 7–8; John 13:34–35). How is it “old”? Not only did Jesus and the apostles teach love, but it was also the greatest commandment from the Old Testament. How is it “new”? Because perfect love is seen in Christ and, by extension, His church. Love is not an abstract quality but a Person. Because of Christ, “the darkness is passing and the true light is already shining.” Exactly as Isaiah prophesied: “On those living in the land of deep darkness a light has dawned” (Isa. 9:2). When we love, we prove that we’re walking in the light (vv. 9–11). If we say we follow Christ, our actions must show love for our brothers and sisters in the faith. If we really are in the same family, we’ll act like it! >> Today’s illustration comes from Bryan Litfin’s Wisdom from the Ancients: 30 Forgotten Lessons from the Early Church. This book will help you learn more about church history and how it applies to our lives today.