Sunan Abi Dawud Book 2, Hadith 136
“And I too, and I too”.
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.
“Allah is most great, Allah is most great”, and one of you says in response: “Allah is most great”, Allah is most great; then says: “ I testify tht there is no god but Allah”, and he says in response: “I testify that there is no god but Allah”, then say:” I testify that Muhammad is the Messenger of Allah”, and he makes the response: “ I testify that Muhammad is the Messenger of Allah”, then says: “Come to prayer”, and he makes the response: “There is no might and no power except in Allah”: then says: “ Allah is most great, Allah is most great”, and he makes the response: “Allah is most great”, then says: “There is no god but Allah”, if he says this from his heart, he enter Paradise.