Sunan Abi Dawud Book 2, Hadith 134
A man said: Messenger of Allah, the mu'adhdhins excel us. The Messenger of Allah (ﷺ) said: Say (the same words) as they say, and when you come to the end, make a petition and that will be granted to you.
when you hear the mu'adhdhin repeat what he says, invoke a blessing on me, for everyone who invoke one blessing on me will receive ten blessings from Allah. Then ask Allah to give me the wasilah, which is a rank in paradise fitting for only one of Allah’s servants, and I hope that I may be the one. If anyone asks Allah that I be given the wasilah, he will be assured of my intercession.
If anyone says when he hears the MU’ADHDHIN : “And I testify that there is no god but Allah alone who has no partner and that Muhammad is His servant and Apostle: I am satisfied with Allah as lord, with Muhammad as apostle and with Islam as religion”, he will be forgiven.