Muwatta Malik, Book 20, Hadith 56 (USC-MSA)

Yahya related to me from Malik that he had heard that the Messenger of Allah, may Allah bless him and grant him peace, did umra three times: in the year of Hudaybiya, in the year of al-Qadiyya, and in the year of al-Jiirrana.

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم اعْتَمَرَ ثَلاَثًا عَامَ الْحُدَيْبِيَةِ وَعَامَ الْقَضِيَّةِ وَعَامَ الْجِعِرَّانَةِ ‏.‏

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also referenced under: Book 20, Hadith 761 (In-Book)