The Messenger of Allah ﷺ announced a military campaign, and I was an old man with no servant. So I looked for a hired hand who could serve me, and I would give him his share of the spoils. I found a man, and when the time of departure drew near, he came to me and said, "I don't know what the shares will amount to, nor what my share will come to. So fix a definite sum for me, whether there is a share or not."I agreed on three dinars for him. When the spoils came in, I wanted to give him his share, but then I remembered the dinars, so I went to the Prophet ﷺ and told him about the matter.He said, "I find nothing for him in this expedition of his, in this world or the next, except the dinars he stipulated."
أذن رسول الله ﷺ بالغزو، وأنا شيخ كبير ليس لي خادم، فالتمست أجيرا يكفينى وأجري له سهمه، فوجدت رجلا، فلما دنا الرحيل أتاني فقال: ما أدرى ما السهمان؟ وما يبلغ سهمى؟ فسم لي شيئا-كان السهم أو لم يكن-. فسميت له ثلاثة دنانير، فلما حضرت غنيمته أردت أن أجرى له سهمه، فذكرت الدنانير فجئت النبى ﷺ فذكرت له أمره فقال: ما أجد له في غزوته هذه في الدنيا والآخرة إلا دنانيره التي سمى.
Reported by Abu Dawud (2527), Hakim (2/112), and from him Bayhaqi (6/331), via Ahmad bin Salih, who said, Abdullah bin Wahb told us, Asim bin Hakeem informed me, from Yahya bin Abu Amr Saybani, from Abdullah bin Daylami, that Yaala bin Munya said, then he related it. Hakim said, "This is a sahih hadith meeting the conditions of the two sheikhs."I say, its chain is hasan because of Asim bin Hakeem, for his hadith is hasan, though neither of the two sheikhs included his reports, or only one of them did. Abu Dawud reported from him, and Bukhari included him in Adab al-Mufrad. The hadith has other routes as well, but what I have mentioned is the soundest of them.As for what is reported from Abu Ayub, that he heard the Messenger of Allah ﷺ say, "Cities will be opened up to you, and there will be organized armies, from which detachments will be assigned to you. A man among you will dislike a certain detachment, and will free himself from his own people, then go around examining the tribes, offering himself to them, saying, 'Who will let me take his place in this detachment?', 'Who will let me take his place in that detachment?' Yet that hired substitute remains a fighter to the very last drop of his blood," this is not sahih.It was reported by Abu Dawud (2525), Ahmad (23500), and Bayhaqi (9/27) through routes from Muhammad bin Harb, from Abu Salama Sulayman bin Sulaym, from Yahya bin Jabir Tai, from the nephew of Abu Ayub Ansari, from Abu Ayub, then he related it.In its chain is the nephew of Abu Ayub Ansari, who is Abu Sura, and he is daif. In fact, Bukhari said, "His hadith is objectionable. He reports objectionable things from Abu Ayub that are not corroborated." He also said, "It is not known whether he actually heard from Abu Ayub."