When someone embraced Islam, the Prophet ﷺ would teach him the prayer, then instruct him to supplicate with these words, "O Allah, forgive me, have mercy on me, guide me, grant me well-being, and provide for me."In another wording, he heard the Prophet ﷺ when a man came to him and asked, "Messenger of Allah, what should I say when I ask my Lord?"He replied, "Say, 'O Allah, forgive me, have mercy on me, grant me well-being, and provide for me,'" and he closed his fingers together except for the thumb, saying, "These words combine for you the good of this world and the next."
كان الرجل إذا أسلم، علمه النبي ﷺ الصلاة، ثم أمره أن يدعو بهؤلاء الكلمات: اللهم اغفر لي، وارحمني، واهدني، وعافني وارزقني وفي لفظ: أنه سمع النبي ﷺ وأتاه رجل، فقال: يا رسول الله كيف أقول حين أسأل ربي؟ قال: قل: اللهم اغفر لي، وارحمني، وعافني وارزقني، ويجمع أصابعه إلا الإبهام، فإن هؤلاء تجمع لك دنياك وآخرتك.
Muslim narrated it in the Book of Remembrance and Supplication (2697:35) from Saeed bin Azhar Wasiti, who said, Abu Muawiya narrated to us, who said, Abu Malik Ashjai narrated to us, from his father, and he mentioned it with the first wording. He also narrated it (2697:36) from Zuhayr bin Harb, who said, Yazid bin Harun narrated to us, who said, Abu Malik informed us, from his father, and he mentioned it with the second wording.