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. (Using translation from Abū Dāʾūd 525)
عَنْ رَسُولِ اللهِ ﷺ قَالَ مَنْ قَالَ حِينَ يَسْمَعُ الْمُؤَذِّنَ وَأَنَا أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللهُ وَحْدَهُ لَا شَرِيكَ لَهُ وَأَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ رَضِيتُ بِاللهِ رِبًّا وَبِمُحَمَّدٍ رَسُولًا وَبِالْإِسْلَامِ دِينًا غُفِرَ لَهُ