Ata bin Abu Rabah reported,

We were with Ibn Umar at Mina when a young man from Basra came to him asking about something. Ibn Umar said, "I will tell you about that. I was with the Messenger of Allah ﷺ as one of ten in his mosque. There were Abu Bakr and Umar, Uthman, Ali, Ibn Masud, Muaz, Hudhayfah, Abu Saeed Khudri, another man whom he named, and myself.A young man from the Ansar came in, greeted the Messenger of Allah ﷺ, then sat down and asked, "Messenger of Allah, which of the believers is most excellent?"He replied, "The one with the best character."The young man asked, "And which of the believers is the most prudent?"He answered, "The one who remembers death the most, and prepares for it best before it comes upon them." Or he said, "Those are the prudent ones."Then the young man fell silent, and the Prophet ﷺ turned to us and said, "Indecency never appears among a people, becoming open and public, without plague and ailments unknown to their predecessors breaking out among them. They never cheat in measure and weight without being seized by famine, hardship of provision, and the tyranny of their ruler. They never withhold the zakat on their wealth without being denied rain from the sky, and were it not for the animals, they would receive no rain at all. They never break the covenant of Allah and His Messenger without Allah giving their enemy power over them, who then takes some of what was in their hands. And whenever their leaders do not govern by the Book of Allah, Allah sets their violence against one another."He said, "Then he ordered Abdul-Rahman bin Awf to prepare for an expedition he was placing him in command of. The next morning, Ibn Awf came wearing a black turban of coarse cloth. The Prophet ﷺ called him over, undid it, and rewound it for him, letting four fingers' length, or thereabouts, hang behind him. Then he said, "This is how you should wear the turban, Ibn Awf. It is more recognizable and better."Then he ordered Bilal to bring him the banner. He praised Allah and said, "Go forth together in the path of Allah. Fight those who disbelieve in Allah. Do not steal from the spoils, do not act treacherously, do not mutilate, and do not kill a child. This is the covenant of Allah and the way of your Prophet among you."

عن عطاء بن أبي رباح قال

كنا مع ابن عمر بمنى فجاءه فتى من أهل البصرة يسأله عن شيء فقال: سأخبرك عن ذلك كنت عند رسول الله ﷺ عاشر عشرة في مسجد رسول الله أبو بكر وعمر وعثمان وعلي وابن مسعود ومعاذ وحذيفة وأبو سعيد الخدري ورجل آخر سماه وأنا فجاءه فتى من الأنصار فسلم على رسول الله ﷺ ثم جلس فقال: يا رسول الله أي المؤمنين أفضل؟ قال: أحسنهم خلقا قال: فأي المؤمنين أكيس؟ قال: أكثرهم للموت ذكرا، وأحسن له استعداداقبل أن ينزل بهم، أو قال به: أولئك الأكياس. ثم سكت الفتى وأقبل علينا النبي ﷺ فقال: لم تظهر الفاحشة في قوم قط حتى يعلنوا بها إلا ظهر فيهم الطاعون والأوجاع التي لم تكن مضت في أسلافهم، ولا نقصوا المكيال والميزان إلا أخذوا بالسنين، وشدة المؤنة، وجور السلطان عليهم، ولم يمنعوا زكاة أموالهم إلا منعوا القطر من السماء، ولولا البهائم لم يمطروا، ولن ينقضوا عهد الله ورسوله إلا سلط الله عليهم عدوهم، وأخذوا بعض ما كان في أيديهم، وإذا لم يحكم أئمتهم بكتاب الله جعل الله بأسهم بينهم. قال: ثم أمر عبد الرحمن بن عوف أن يتجهز لسرية أمره عليها، فأصبح قد اعتم بعمامة كرأبيس سوداء، فدعاه النبي ﷺ، فنقضها، فعممه وأرسل من خلفه أربع أصابع أو نحوها، ثم قال: هكذا يا ابن عوف فاعتم، فإنه أعرف وأحسن، ثم أمر بلالا، أن يرفع إليه اللواء، فحمد الله، ثم قال: اغزوا جميعا في سبيل الله، قاتلوا من كفر بالله، لاتغلوا، ولا تغدروا، ولا تمثلوا، ولاتقتلوا وليدا، فهذا عهد الله وسنة نبيكم فيكم.