A believer has two forces at war inside. Before Christ found you, you lived under one power only: darkness. But now light has broken in, and these two powers cannot coexist peacefully.

Mark well the apostle Paul's words in Romans 7: "I find this principle at work: when I want to do good, evil is right there with me. For in my inner being I delight in God's law. But I see another power operating in my body, waging war against the law of my mind and making me a prisoner to the law of sin at work within me."

How did this civil war begin? Simple. "The Lord divided the light from the darkness." Darkness, left alone, is perfectly content. Quiet. Undisturbed. But when God sends in his light, war breaks out! Light and darkness are sworn enemies. And this conflict will rage until the day we become altogether light in the Lord.

But here's what you must understand: if there's division inside the Christian, there will certainly be division outside. The moment God gives anyone his light, that person begins to separate from the darkness around them. They can no longer stomach a religion of empty rituals and outward show. Nothing but the raw gospel of Christ will satisfy now. They withdraw from worldly society and frivolous amusements and seek out the company of the saints. "We know that we have passed from death to life, because we love the brethren."

Light gathers to light. Darkness huddles with darkness. What God has divided, let us never try to unite! Christ went outside the camp, bearing his reproach. So we too must come out from among the ungodly and be a peculiar people. He was holy, harmless, undefiled, separate from sinners. And as he was, so we are called to be—nonconformists to this world's ways, dissenters from all sin, distinguished from the rest of mankind by our likeness to our Master.

This is not optional. This is what happens when light invades darkness.