Staying in the Light

In Him was life, and that life was the light of men.
John 1:3

I have come into the world as a light, so that no one who believes in me should stay in darkness.
John 12:46

Read these 2 nuggets again slowly ...
He is the Light of men, he came to illuminate and draw us from darkness once and for all. At the risk of stating the obvious here, darkness is, by definition, the absence of light. Why would anyone who believes in Jesus want to remain shrouded in darkness? The enemy is a deceiver, liar, accuser of the brethren, the destroyer. Light illuminates his bag of dark tricks.
It's not just enough to believe though! The Scriptures tell us "even the demons believe in Jesus - and shudder". We are given an arsenal to do battle against darkness, but the arsenal is useless unless the weapons are wielded. We need to have the light for this reason.

Thy Word is a Lamp unto my feet and a light unto my path.

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