Imran bin Husayn reported,

Husayn, or Husayn, came to the Messenger of Allah ﷺ and said, "Muhammad, Abdul-Muttalib was better to his people than you. He used to feed them liver and hump, while you slaughter them."The Prophet ﷺ said to him whatever Allah willed him to say.Then the man asked, "What do you command me to say?"He replied, "Say, 'O Allah, protect me from the evil of myself, and resolve me upon the most rightly guided course of my affair.'"The man went off and embraced Islam. Then he came back and said, "I came to you before, and you told me to say, 'O Allah, protect me from the evil of myself, and resolve me upon the most rightly guided course of my affair.' What should I say now?"He answered, "Say, 'O Allah, forgive me what I have concealed and what I have made public, what I have done by mistake and what I have done deliberately, what I have known and what I have been ignorant of.'"

Azami 11300

Sahih

عن عمران بن حصين

أن حصينا أو حصينا أتى رسول الله ﷺ فقال: يا محمد، لعبد المطلب كان خيرا لقومه منك، كان يطعمهم الكبد والسنام، وأنت تنحرهم، فقال له النبي ﷺ ما شاء الله أن يقول، فقال له ما تأمرني أن أقول، قال: قل: اللهم قني شر نفسي واعزم لي على أرشد أمري، قال: فانطلق فأسلم الرجل ثم جاء فقال: إني أتيتك فقلت لي: قل: اللهم قني شر نفسي واعزم لي على أرشد أمري فما أقول الآن؟ قال: قل: اللهم اغفر لي ما أسررت وما أعلنت وما أخطأت وما عمدت وما علمت وما جهلت.

الأعظمي 11300صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Supplications, remembrances, and prayer upon the chosen Prophet ﷺ
Chapter
Supplications for various occasions
Section
What one who is newly converted to Islam should supplicate
Numbering
Jami al-Kamil 11300 (2nd edition)
Azami 11300