Musannaf Ibn Abi Shaybah

Ya'la bin Harmalah (may Allah be pleased with him) narrates that Hajjaj delivered a speech in the plain of Arafat on the day of Arafah and spoke at great length. Abdullah bin Umar (may Allah be pleased with them both) said to him, "Today is a day of remembrance (dhikr)." He says that Hajjaj continued his sermon. Abdullah repeated this statement two or three times, then said, "O Nafi', give the call to prayer (adhan) for the prayer." Hearing this, Hajjaj descended from the pulpit.