What is evil? - John Piper

"What is evil? What is ultimate evil according to Jeremiah 2:13?

Be appalled, O heavens at this; be shocked, be utterly [dismayed]...for my people have committed two [great] evils: they have forsaken me, the fountain of living waters, and hewed out cisterns for themselves, broken cisterns that can hold no water. (Jeremiah 2:12-13)

That's evil. So what is evil? Evil is to be presented by the Living God with a fountain of water that will carry you into eternity and satisfy your heart forever and ever—never ending—and then to turn your nose at it! Then you turn around and take a little shovel and start digging in dry dirt, putting your mouth to it, trying to get something satisfying out of it. That's evil!

This means that to do good — the opposite of evil—is to be a hedonist. Go to the Fountain! The opposite of coming to the fountain is evil. The essence of coming to the fountain is drinking and drinking until it satisfies your soul, and you say, "Ah!" And then you begin to commend it in Indonesia, Pakistan, China, Saudi Arabia, North Korea, Cuba, and Vietnam at cost to your life.”

John Piper, Let Your Passion Be Single

http://www.desiringgod.org/ResourceLibrary/ConferenceMessages/ByDate/1999/1814_Let_Your_Passion_Be_Single/