When the Kharijites rebelled at Nahrawan, Ali stood up among his companions and said, "These people have shed unlawful blood and raided the people's grazing livestock. They are the nearest enemy to you. If you march out against your other enemy, I fear that these people will fall upon you from behind. I heard the Messenger of Allah ﷺ say, 'A group will emerge from my nation whose prayer will make yours seem as nothing, whose fasting will make yours seem as nothing, and whose recitation will make yours seem as nothing. They will recite the Quran thinking it counts in their favor, while it actually counts against them. It will not pass beyond their throats. They will pass through Islam as an arrow passes through its prey. The sign of this is that among them is a man with an upper arm but no forearm, on it is something like the nipple of a breast with white hairs on it. If the army that defeats them knew what has been promised them on the tongue of their Prophet, they would rely on this deed alone. So march, in the name of Allah.'"Then he mentioned the hadith in its full length.
حدثنا عبد الله حدثنا أحمد بن جميل أبو يوسف أخبرنا يحيى بن عبد الملك بن حميد بن أبي غنية عن عبد الملك بن أبي سليمان عن سلمة بن كهيل
لما خرجت الخوارج بالنهروان قام علي رضي الله عنه في أصحابه فقال إن هؤلاء القوم قد سفكوا الدم الحرام وأغاروا في سرح الناس وهم أقرب العدو إليكم وإن تسيروا إلى عدوكم أنا أخاف أن يخلفكم هؤلاء في أعقابكم إني سمعت رسول الله ﷺ يقول تخرج خارجة من أمتي ليس صلاتكم إلى صلاتهم بشيء ولا صيامكم إلى صيامهم بشيء ولا قراءتكم إلى قراءتهم بشيء يقرءون القرآن يحسبون أنه لهم وهو عليهم لا يجاوز حناجرهم يمرقون من الإسلام كما يمرق السهم من الرمية وآية ذلك أن فيهم رجلا له عضد وليس لها ذراع عليها مثل حلمة الثدي عليها شعرات بيض لو يعلم الجيش الذين يصيبونهم ما لهم على لسان نبيهم لاتكلوا على العمل فسيروا على اسم الله فذكر الحديث بطوله
Its isnad is sahih. Ahmad bin Jameel Marwazi is trustworthy. Yahya bin Abdul-Malik bin Humayd bin Abu Ghaniyya Khuzai Kufi is trustworthy. Abdul-Malik bin Abu Sulayman is al-Marzami. Salama bin Kuhayl is Hadrami Tanei, with a kasra on the ta, a sakin on the nun, and a plain ain, a name derived from Tana, a clan of Hamdan. He was a trustworthy successor, firmly reliable and precise in hadith.See 672 and 735. This hadith is abridged, as indicated at its end, and it is not mentioned again elsewhere in the Musnad. Other hadiths concerning the Khawarij have already passed, and more will come. This is one of the additions of Abdullah bin Ahmad.Sarh refers to livestock that is sent out to graze. It is a collective noun, or it may be a naming derived from the verbal noun.