I think we're going to the moon because it's in the nature of the human being to face challenges. It's by the nature of his deep inner soul... we're required to do these things just as salmon swim upstream. Neil Armstrong
The universe is not required to be in perfect harmony with human ambition. Carl Sagan
There lies at the back of every creed something terrible and hard for which the worshipper may one day be required to suffer. E. M. Forster
Money is not required to buy one necessity of the soul. Henry David Thoreau
Life is the only art that we are required to practice without preparation, and without being allowed the preliminary trials, the failures and botches, that are essential for training. Lewis Mumford
I can't imagine anything worse than being required to have fun. Scott Westerfeld