The Messenger of Allah ﷺ said, "When the great battles take place, Allah will send forth a contingent of freed slaves who will be the noblest of the Arabs in horsemanship and the finest in weaponry. Through them, Allah will strengthen the religion."
حدثنا هشام بن عمار حدثنا الوليد بن مسلم حدثنا عثمان بن أبي العاتكة عن سليمان بن حبيب المحاربي
قال رسول الله ﷺ إذا وقعت الملاحم بعث الله بعثا من الموالي هم أكرم العرب فرسا وأجوده سلاحا يؤيد الله بهم الدين
[Its chain is hasan] Hakim recorded it (4/848) from the hadith of Uthman through this route, and he graded it sahih according to the criterion of Bukhari, and Dhahabi agreed with him according to the criterion of Muslim. Busiri said, "This chain is hasan, Uthman is disputed about." I say, the majority of scholars deemed him reliable, except regarding Ali bin Yazid Alhani.