The Prince by Niccolo Machiavelli Chapter 9 Page 9

the citizens and subjects who are accustomed to take their orders from the magistrates, will not when dangers threaten take them from the Prince, so that at such seasons there will always be very few in whom he can trust. Such Princes, therefore, must not build on what they see in tranquil times when the citizens feel the need of the State. For then every one is ready to run, to promise, and, danger of death being remote, even to die for the State. But in troubled times, when the State has need of its citizens, few of them are to be found. And the risk of the experiment is the greater in that it can only be made once. Wherefore, a wise Prince should devise means whereby his subjects may at all times, whether favourable or adverse, feel the need of the State and of him, and then they will always be faithful to him.