Without hard work, nothing grows but weeds.
If you can dream it, you can do it.
Be gentle to all and stern with yourself.
Leap, and the net will appear.
The wise does at once what the fool does at last.
Well done is better than well said.
Things do not happen. Things are made to happen.
It's always too early to quit.
Either you run the day or the day runs you.
Problems are not stop signs, they are guidelines.
Triumphant science and technology are only at the threshold of man's command over sources of energy so stupendous that, if used for military purposes, they can wipe out our entire civilization.