Darkness cannot drive out darkness, only light can do that. Hate cannot drive out hate, only love can do that.

In the end, we will remember not the words of our enemies, but the silence of our friends.

I submit to you that if a man hasn't discovered something he will die for, he isn't fit to live.

Our scientific power has outrun our spiritual power. We have guided missiles and misguided men.

The ultimate measure of a man is not where he stands in moments of comfort, but where he stands at times of challenge and controversy.