Mu'jam Kabir Tabarani 16824 — I heard Muhammad bin Yusuf, the freed

Abd al-Aziz bin al-Rabi' bin Sabrah (may Allah have mercy on him) said: I heard Muhammad bin Yusuf, the freed slave of Uthman (may Allah have mercy on him), say: It was the practice of Sayyiduna Mu'awiyah (may Allah be pleased with him) that when the mu'adhdhin called the adhan, he would say the same, until, when he said "Hayya 'ala al-salah, hayya 'ala al-falah" (Come to prayer, come to success), he would say: "La hawla wa la quwwata illa billah" (There is no power to avoid sin nor strength to do good except through Allah's help). Then he would say the same as the rest of what he said, and then he said: "This is how I heard the Messenger of Allah (peace and blessings be upon him) say it."