On why he has donated $600 million to selected charities. I simply decided I had enough money.

I cannot think of a more personally rewarding and appropriate use of wealth than to give while one is living - to personally devote oneself to meaningful efforts to improve the human condition. More importantly, today's needs are so great and varied that intelligent philanthropic support and positive interventions can have greater value and impact today than if they are delayed when the needs are greater.

I’m happy when what I’m doing is helping people and unhappy when what I’m doing isn’t helping people.

I believe strongly in 'giving while living.' I see little reason to delay giving when so much good can be achieved through supporting worthwhile causes today.

I set out to work hard, not to get rich.

I cannot think of a more personally rewarding and appropriate use of wealth than to give while one is living.... Interventions have greater value and impact today than if they are delayed.

There has to be a balance in life. A balance of business, family, and the opportunity to learn and teach.