Joy changes everything, including our battle against evil.
John Piper explains in this two-minute video:
Christian Hedonism changes our combat with evil. Jeremiah 2:13 — the Christian Hedonist definition of evil — "for my people have committed two evils: they have forsaken me, the fountain of living waters, and hewed out cisterns for themselves, broken cisterns that can hold no water."
What's evil? The suicidal preference of empty wells over the river of delights flowing from heaven. That's evil!
So the battle against evil is not to constantly say "No, no, no. Bad, bad, bad." There's no power in that. The power of the flesh is coming at you, the power of the devil is coming at you, and you're going to [muster] up your willpower and make that the victory? You're not. You're not.
One thing will give you the victory: Faith is the victory that overcomes the world. And faith is a being satisfied in all that God is for us in Jesus Christ. You've got to stoke that engine every morning so that the evils that are clawing at you lose its fangs. You can't have me, I've seen Jesus this morning. Lust, you can't have me. Greed, you can't have me. Fear of man, you can't have me. Bitterness and anger, you can't have me. I've seen Jesus this morning.
The battle against evil is totally transformed by Christian Hedonism.
This excerpt was taken from the recent sermon, "God Is Most Glorified in Us When We Are Most Satisfied in Him."