Sa’d b. Abu Waqqas reported: The Messenger of Allah (may peace be upon him) said: If anyone says on hearing the Mu’adhdhin:

وَأَنا أَشْـهَدُ أَنْ لا إِلـهَ إِلاّ اللهُ وَحْـدَهُ لا شَـريكَ لَـه ، وَأَنَّ محَمّـداً عَبْـدُهُ وَرَسـولُه ، رَضيـتُ بِاللهِ رَبَّاً ، وَبِمُحَمَّـدٍ رَسـولاً وَبِالإِسْلامِ دينَـاً .

Wa ‘anaa ashhadu an laa ilaaha illal-laahu wahdahu laa shareeka lahu, wa ‘anna Muhammadan ‘abduhu wa Rasooluhu, radheetu billaahi Rabban, wa bi Muhammadin Rasoolan wabil-islami deenan.

‘I bear witness that none has the right to be worshipped but Allaah alone, Who has no partner, and that Muhammad is His Slave and His Messenger. I am pleased with Allah as my Lord, with Muhammad as my Messenger and with Islam as my religion.’

his sins would be forgiven [1]

[To be recited in Arabic after the Mu’aththin’s Tashahhud or the words of affirmation of faith][2]

[1] Muslim 1/290
[2] Ibn Khuzayma 1/220

“Whoever ate something, then said:  الْحَمْـدُ للهِ الَّذي أَطْعَمَنـي هـذا وَرَزَقَنـيهِ مِنْ غَـيْرِ حَوْلٍ مِنِّي وَلا قُوَّة

Al-Hamdu lillaahilladhee at’amanee hadha wa razaqneeh min ghayri hawlin minnee wa la quwwa
‘Praise be to Allah who has fed me this food and provided it for me, without any strength or power on my part’
is forgiven his past and future sins.

[‘Sahih al-Jami’ #6086]