Abd al-Rahman bin Ka'b bin Malik (may Allah have mercy on him) said: I used to lead my father (Ka'b bin Malik, may Allah be pleased with him) to the mosque after his sight was gone. Once I was taking him to the Friday prayer, and upon hearing the call to prayer my father prayed for forgiveness for Abu Umamah As'ad bin Zurarah (may Allah be pleased with him). I waited for some time and kept hearing this from him, but did not ask. Then I took him out for the Friday prayer, and when he heard the call to the Friday prayer he prayed for forgiveness for As'ad bin Zurarah (may Allah be pleased with him). I asked: O my dear father! Do you pray for forgiveness for As'ad bin Zurarah (may Allah be pleased with him) whenever you hear the call to the Friday prayer? He said: O my son! As'ad (may Allah be pleased with him) was the first man to lead us in the Friday prayer in Madinah, before the Prophet (peace and blessings be upon him) arrived, in Hazm, the settlement of Banu Bayadah in the area of Naqi'. It was called al-Khadamat. I asked: How many of you were there that day? He said: Forty men.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5605