Saad bin Abi Waqqas reported the Messenger of Allah ﷺ as saying: If anyone says when he hears the MuadhDHIN: “And I testify that there is no god but Allah alone who has no partner and that Muhammad is His servant and Messenger: I am satisfied with Allah as lord, with Muhammad as Messenger and with Islam as religion”, he will be forgiven.
Hadith Referenceسنن ابي داود / كتاب الصلاة / 525
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح مسلم (386)