مُوَطَّأُ مَالِكٍ
Muwatta Malik 710
Hajj
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَغْتَسِلُ لإِحْرَامِهِ قَبْلَ أَنْ يُحْرِمَ وَلِدُخُولِهِ مَكَّةَ وَلِوُقُوفِهِ عَشِيَّةَ عَرَفَةَ .
Yahya related to me from Malik from Nafi' that 'Abdullah ibn Umar used to do ghusl for ihram before he entered ihram, and for entering Makka, and for standing on the afternoon of 'Arafa.
Arabic/English book reference: Book 20, Hadith 3