Prior to embarking on the Expedition to Tabuk in 631, Muhammad designated Ali to remain in Medina and govern in his absence. According to Ibn Hisham, one of the earliest available sources of this "hadith", Ali heard suggestions that he had been left behind because Muhammad had found his presence a burden. Ali immediately took his weapons and followed in pursuit of the army, catching up with them in an area called al-Jurf. He relayed to Muhammad the rumours, to which the latter responded "They lie. I left you behind because of what I had left behind, so go back and represent me in my family and yours. Are you not content, Ali, to stand to me as Aaron stood to Moses, except that there will be no prophet after me?" Ali then returned to Medina and took up his position as instructed.