Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

"I used to guide my father after he lost his sight, and when I took him out for the Friday (prayer), when he heard the Adhan he would pray for forgiveness for Abu Umamah As'ad bin Zurarah, and supplicate for him. I heard that from him for a while, then I said to myself: 'By Allah! What is this weakness? Every time he heard the Adhan for Friday (prayer) I hear him praying for forgiveness for Abu Umamah and supplicate for him, and I do not ask him about why he does that.' Then I took him out for Friday (prayer), as I used to take him out, and when he heard the Adhan he prayed for forgiveness as he used to do. I said to him: 'O my father! I see you supplicating for As'ad bin Zurarah every time you hear the call for Friday; why is that?' He saud: 'O my son, he was the first one who led us for the Friday prayer before the Messenger of Allah (saw) came from Makkah, in Naqi' Al- Khadamat (a place near Al-Madinah), in the plain of Harrah Banu Bayadah.' I asked: 'How many of you were there at that time?' He said: 'Forty men.'" Sahih