مُوَطَّأُ مَالِكٍ
Muwatta Malik 432
The Two 'Ids
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَغْتَسِلُ يَوْمَ الْفِطْرِ قَبْلَ أَنْ يَغْدُوَ إِلَى الْمُصَلَّى .
Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to do ghusl on the day of Fitr before going to the place of prayer.
Arabic/English book reference: Book 10, Hadith 2