It is narrated from Sayyiduna Buraydah (may Allah be pleased with him) that whenever the Prophet (peace and blessings be upon him) dispatched an expedition or a large army, he would especially advise its commander to adopt the fear of Allah (taqwa) in his own personal affairs, and would urge him to treat the Muslims with him well. Then he (peace and blessings be upon him) would say: "Fight in the name of Allah; fight those who disbelieve in Allah. Do not steal from the spoils, do not break covenants, do not mutilate the slain, and do not kill any child. When you meet your enemy from among the polytheists, invite them to Islam. If they accept it, accept it from them and refrain from them. Then invite them to move from their homes to the abode of the Muslims. If they do so, accept it from them; otherwise inform them that they will be like the Bedouin Muslims, upon whom the same ruling of Allah applies as applies to the Muslims in general, but they will have no share in the fay' or in the spoils of war. Then, if they refuse Islam, demand the jizyah from them. If they agree to it, accept it from them and hold back from them. When you besiege a fortress or a city and the enemy wants you to bring them down on the judgement of Allah (that is, to make terms according to the decision of Allah), do not bring them down on the judgement of Allah, for you do not know what Allah's actual judgement concerning them is; rather, bring them down on your own judgement and then decide about them as you see fit. And when you besiege a palace, do not give them the covenant (guarantee of protection) of Allah and His Messenger; rather, give them your own covenant and that of your forefathers, for it is far lighter for you to break your own covenant or that of your forefathers than to violate the covenant of Allah and His Messenger."
Hadith Referenceمسند أبي يعلى الموصلي / مسند بريدة / 1413
Hadith Takhrij«قال سعيد بن محمد السناري: صحيح» «أخرجه صحيح مسلم برقم: 1731، وأخرجه سنن الترمذي برقم: 1408، 1617، وأخرجه سنن أبي داود برقم: 2612، 2613، وأخرجه سنن ابن ماجه برقم: 2858، وأخرجه مسند أحمد برقم: 22469، 22521، وأخرجه سنن الدارمي برقم: 2439، 2442، وأخرجه مسند البزار برقم: 3122، وأخرجه المعجم الأوسط للطبراني برقم: 135، 1453، وأخرجه المعجم الصغير للطبراني برقم: 314، وأخرجه معرفة السنن والآثار برقم: 18472، وأخرجه الأموال لابن زنجويه برقم: 102، 757، مسند ابویعلیٰ ترقیم الاثری: 1409»