سنن النسائي

It was narrated that 'Alqamah bin Waqqas said: "I was with Mu'awiyah when the Mu'adhdhin called the Adhan. Muawiyah said what the Mu'adhdhin said, but when he said: 'Hayya 'alas-salah (come to prayer),' he said: 'La hawla wa la quwwata illa Billah (There is no power and no strength except with Allah);' and when he said: 'Hayya 'alal-falah (come to prosperity),' he said: 'La hawla wa la quwwata illa Billah (There is no power and no strength except with Allah).' After that he said what the Mu'adhdhin said, then he said: 'I heard the Messenger of Allah (S.A.W) saying exactly like that.'"