Messenger of Allah said: "Whoever says, when he hears the Mu'adh-dhin: (Wa Ana Ashadu An La Ilaha Illallah, Wahdahu La Sharika Lahu, Wa Anna Muhammadan Abduhu Wa Rasuluhu, Radittu Billahi Rabban Wa Bil-Islam Dinan, Wa Bi Muhammadin Rasulan) 'I too testify that none has the right to be worshiped but Allah, Alone without partners, and that Muhammad is His slave and Messenger, I am pleased with Allah as my Lord, with Islam as my religion and Muhammad as a Messenger.' - Allah will pardon his sins for him."  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ مَنْ قَالَ حِينَ يَسْمَعُ الْمُؤَذِّنَ وَأَنَا أَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَحْدَهُ لاَ شَرِيكَ لَهُ وَأَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ رَضِيتُ بِاللَّهِ رَبًّا وَبِمُحَمَّدٍ رَسُولاً وَبِالإِسْلاَمِ دِينًا غُفِرَ لَهُ ذَنْبُهُ