Sahih Muslim , Book 48, Hadith 44 (In-Book) ⓘ

Abu Malik Ashaja'i reported on the authority of his father that whenever a person embraced Islam, Allah's Messenger instructed him to recilte: " O Allah, grant me pardon, have mercy upon me, direct me to the path of righteousness and provide me sustenance."

حَدَّثَنَا أَبُو كَامِلٍ الْجَحْدَرِيُّ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، - يَعْنِي ابْنَ زِيَادٍ - حَدَّثَنَا أَبُو مَالِكٍ الأَشْجَعِيُّ عَنْ أَبِيهِ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُعَلِّمُ مَنْ أَسْلَمَ يَقُولُ ‏ "‏ اللَّهُمَّ اغْفِرْ لِي وَارْحَمْنِي وَاهْدِنِي وَارْزُقْنِي ‏" ‏ ‏.‏