This is a quote from John Piper given at One Day 2000:
"You don't have to know a lot of things for your life to make a lasting difference in the world. But you do have to know the few great things that matter, and then be willing to live for them and die for them. The people that make a durable difference in the world are not the people who have mastered many things, but who have been mastered by a few great things. If you want your life to count, if you want the ripple effect of the pebbles you drop to become waves that reach the ends of the earth and roll on for centuries and into eternity, you don't have to have a high IQ or EQ; you don't have to have to have good looks or riches; you don't have to come from a fine family or a fine school. You have to know a few great, majestic, unchanging, obvious, simple, glorious things, and be set on fire by them."
Here is a link to the audio:
There is no substitute for hearing, not just reading, John Piper. The emotional power that comes through in his spoken word has gotten through to my heart in ways that merely reading his messages have not.