Musannaf Ibn Abi Shaybah 2254 — Those who said the adhan is unhurried

Abu al-Zubayr, the muezzin of Bayt al-Maqdis, said: Sayyiduna Umar (may Allah be pleased with him) came to us and said: "When you give the adhan, say it slowly and deliberately, and when you give the iqamah, say it quickly."