The Prince by Niccolo Machiavelli Chapter 8 Page 11

renewed severities, will never yield him their confidence. Injuries, therefore, should be inflicted all at once, that their ill savour being less lasting may the less offend; whereas, benefits should be conferred little by little, that so they may be more fully relished.

But, before all things, a Prince should so live with his subjects that no vicissitude of good or evil fortune shall oblige him to alter his behaviour; because, if a need to change come through adversity, it is then too late to resort to severity; while any leniency you may use will be thrown away, for it will be seen to be compulsory and gain you no thanks.