When the Messenger of Allah (ﷺ) ordered a namus (a bell or wooden clapper) to be made to be struck for gathering people to prayer, there hovered around me while I was sleeping a man carrying a namus in his hand. I said, 'O servant of Allah, will you sell the namus?' He asked, 'What will you do with it?' I replied, 'We will call the people to prayer with it.' He said, 'Shall I not guide you to something better than that?' I replied, 'Certainly.' He said, 'You should say: Allahu Akbar, Allahu Akbar, Allahu Akbar, Allahu Akbar (Allah is the Greatest, Allah is the Greatest, Allah is the Greatest, Allah is the Greatest); Ashhadu an la ilaha illallah, Ashhadu an la ilaha illallah (I bear witness that there is no god but Allah, I bear witness that there is no god but Allah); Ashhadu anna Muhammadan Rasulullah, Ashhadu anna Muhammadan Rasulullah (I bear witness that Muhammad is the Messenger of Allah, I bear witness that Muhammad is the Messenger of Allah); Hayya 'ala-s-salah, Hayya 'ala-s-salah (Come to the prayer, Come to the prayer); Hayya 'ala-l-falah, Hayya 'ala-l-falah (Come to success, Come to success); Allahu Akbar, Allahu Akbar (Allah is the Greatest, Allah is the Greatest); La ilaha illallah (There is no god but Allah).'
He then stepped back slightly and said: 'When you stand for the Iqamah, you should say: Allahu Akbar, Allahu Akbar (Allah is the Greatest, Allah is the Greatest); Ashhadu an la ilaha illallah (I bear witness that there is no god but Allah); Ashhadu anna Muhammadan Rasulullah (I bear witness that Muhammad is the Messenger of Allah); Hayya 'ala-s-salah (Come to the prayer); Hayya 'ala-l-falah (Come to success); Qad qamatis-salah, Qad qamatis-salah (The prayer has been established, The prayer has been established); Allahu Akbar, Allahu Akbar (Allah is the Greatest, Allah is the Greatest); La ilaha illallah (There is no god but Allah).'
When morning came, I went to the Messenger of Allah (ﷺ) and informed him of what I had seen. He said, 'Indeed, it is a true vision, if Allah wills. Stand up with Bilal and impart it to him, and let him make the call with it, for he has a louder voice than you.' So I stood up with Bilal, and I began to dictate it to him while he made the call to prayer. Umar ibn al-Khattab heard that while he was in his house, so he came out dragging his cloak and saying, 'By Him Who sent you with the truth, O Messenger of Allah, I have seen the very likes of what he saw.' The Messenger of Allah (ﷺ) said, 'To Allah belongs all praise.'
Abu Dawud said: This is the narration of al-Zuhri from Sa'id ibn al-Musayyib from Abdullah ibn Zaid, and Ibn Ishaq said in it: "Allahu Akbar, Allahu Akbar, Allahu Akbar, Allahu Akbar," and Ma'mar and Yunus said from al-Zuhri in it: "Allahu Akbar, Allahu Akbar," and they did not repeat it twice.