Sayyiduna Abu Firas (may Allah have mercy on him) said: Sayyiduna Umar (may Allah be pleased with him) addressed us in a sermon and said: O people! I do not send governors to you so that they beat your bodies and take your wealth; I send them so that they teach you your religion and your Sunnah. If any of them does anything other than this, bring his case to me and I will take retribution from him. Beware! Do not beat the Muslims and so humiliate them; do not drive the Muslims to disbelief by repeatedly scolding and denying them; and do not keep the fighters from returning to their homes, for if you keep them, they will fall into trial; and do not ruin the fighters by putting them on difficult paths.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17848