John’s recollection of Jesus’ ministry, as a man who walked alongside of Him, is crucial for us because it teaches us exactly who Jesus is.  It demonstrates that His light shines in the darkness to reveal the goodness of God (which provides us rescue) and because His life comes from God it cannot be overtaken by our flaws, insecurities, or even our own sinful choices.  In effect, it means that because of Who He is, even our darkest wickedness cannot outshine or undo the hope that Jesus brings!