You become what you worship: individual characters are determined by the character of the god whom they worship. John begins his letter by addressing the very nature of God. Who is this God whom Christians worship? What is the essential differences between Him and gods whom others worship? One of the issues for me is when people say that it doesn't matter which path you follow, each one leads you to God: but what God and thus, what makes our God supreme? Well, one of many things is that He is holy, that is He is light and has no darkness. When Christian believers devote their lives to following and worshipping Him, their lives are changed from the inside out to reflect the glorious nature of the Holy Trinity. So, John's statement tells us FIVE things about God here: 1. He is splendour and glory. His light pierces the darkness. I think I've written previously speculating about the effect of the coming of Jesus into the world and one thing is clear that there was a huge amount of darkness, that demon possession seemed common place. 2. God is self-revealing. There is nothing secretive about Him, He wishes to be seen and known. He is the God who seeks to cast His light upon broken humans, to bring healing and wholeness. 3. His purity and holiness. 4. His guidance. When all around is darkness and we cannot see the way ahead, His light pierces through the murk. 5. He reveals the flaws and stains, the imperfections of life, are seen when in the presence of God.