To Aswad bin Qatiba, the Governor of Hulwan.
After glorifying Allah and praising the Holy Prophet (s) let it be known to you that if a ruler develops different inclinations and favours about different people over whom he rules, then his treatment with them will not be on the basis of equity and impartiality. And this will not allow him to be just and fair to all. But so far as justice and equity are concerned your treatment of all should be fair and unprejudiced. Remember that nothing can compensate for tyranny and oppression.
Keep yourself away from what you consider bad and evil in others. Try your best to fulfill the obligations laid down by Allah upon you and keep on hoping for His Reward and fear His Wrath because this world is a place for trials and tests and whoever wastes his time here will repent in the Hereafter.
Remember that nothing will ever make you independent of the Blessings of Allah and He has made it incumbent upon you to have complete control over your own self, that you, to the best of your ability, protect and guard the people over whom you rule. In this way you will be benefited more than others whom you benefit.