Musnad Ahmad 30:1838

Ali ibn Bahr narrated to us, Hisham ibn Yusuf narrated to us, Ma'mar informed us, from al-Zuhri, from Abu Salamah, from Abu Hurairah, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "For every prophet there is a supplication. I wish—if Allah wills—to store my supplication for the Day of Resurrection as an intercession for my nation."