Ali had stayed behind from the Prophet ﷺ during the expedition to Khaybar because he was suffering from an eye ailment. He said, "Am I to stay behind from the Messenger of Allah ﷺ?" So Ali set out and caught up with the Prophet ﷺ.On the evening before the morning in which Allah granted the victory, the Messenger of Allah ﷺ said, "Tomorrow I will surely give the banner," or he said, "the banner will surely be taken by a man whom Allah and His Messenger love," or he said, "who loves Allah and His Messenger. Allah will grant victory through him."Then suddenly there was Ali, though we had not been expecting him. The people said, "This is Ali." So the Messenger of Allah ﷺ gave him the banner, and Allah granted victory through him.
حدثنا قتيبة حدثنا حاتم عن يزيد بن أبي عبيد
كان علي قد تخلف عن النبي ﷺ في خيبر وكان به رمد فقال أنا أتخلف عن رسول الله ﷺ فخرج علي فلحق بالنبي ﷺ فلما كان مساء الليلة التي فتحها الله في صباحها قال رسول الله ﷺ لأعطين الراية أو ليأخذن الراية غدا رجلا يحبه الله ورسوله أو قال يحب الله ورسوله يفتح الله عليه فإذا نحن بعلي وما نرجوه فقالوا هذا علي فأعطاه رسول الله ﷺ الراية ففتح الله عليه