“But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.”  
1John 1:7

The first thing we notice in the main verse is the fact that by being born again we were placed in the same class as God himself! All of a sudden, our mental and spiritual capacities have been so invigorated that we can walk in the light that God dwells in!
The understanding of every being would be influenced by the light under which he sees, and so a man who sees a white cloth under blue light would argue with the one who sees the same cloth under a red light. When the light is brighter, it means one can have a clearer picture of the objects under the light, much more than the person who is viewing under a dimmer light.
God sees with ‘a light’ and that’s why he has an understanding of situations that is different from humans. He himself is light; so he sees through himself.
When the main verse says “But IF we walk in the light, as he is in the light,” It means we can! Glory to God! It is now possible for us to understand situations the way God understands them; we can get to a place where if something happens, our understanding and consequent response would be exactly the way God understands and would respond with exactly the same results. All of a sudden, we can be (and have become) just like Jesus:
“Who being the brightness of his glory, and the express image of his person…”  Hebrews 1:3, KJV
“He is the reflection of God’s glory and the exact likeness of his being…”  Hebrews 1:3, ISV