Musannaf Ibn Abi Shayba 28:1158

'Abd al-Rahim ibn Sulayman narrated to us, from Yazid ibn Abi Ziyad, from 'Abd al-Rahman ibn Abi Layla, who said: 'Abdullah ibn 'Umar narrated to me that he was in one of the military expeditions of the Messenger of Allah (may Allah bless him and grant him peace). The people retreated in a retreat, and I was among those who retreated. He said: We said when we fled from the battle line, "What shall we do, for we have returned with wrath?" So we said, "Let us enter Medina and spend the night there, so that no one sees us." He said: When we entered, we said, "If only we presented ourselves to the Messenger of Allah (may Allah bless him and grant him peace); if there is repentance for us, we shall stay, and if it is otherwise, we shall depart." He said: So we sat with the Messenger of Allah (may Allah bless him and grant him peace) before the morning prayer. When he came out, we stood up to him and said, "O Messenger of Allah, we are the ones who fled." He said: He turned to us and said, "Nay, you are the ones who return to the fight (al-'akkarun)." He said: We drew near and kissed his hand, and we said, "O Messenger of Allah, we intended to do such and such, and to do such and such." He said, "I am the troop (fi'ah) of the Muslims."