Muwatta Imam Malik Book of Hajj, Hadith 4

Yahya related to me from Malik from Zayd ibn Aslam from Ibrahim ibn Abdullah ibn Hunayn from his father Abdullah ibn Hunayn that Abdullah ibn Abbas and al-Miswar ibn Makhrama once had a disagreement at al-Abwa. Abdullah said that some one in ihram could wash his head, and al Miswar ibn Makhrama maintained that some one in ihram could not wash his head.
Abdullah ibn Hunayn continued, "Abdullah ibn Abbas sent me to Abu Ayyub al-Ansari, and I found him doing ghusl between the posts of a well, screened by a garment. I greeted him and hesaid, 'Who is that?' I replied, 'I am 'Abdullah ibn Hunayn. 'Abdullah ibn Abbas sent me to you to ask how the Messenger of Allah ﷺ used to wash his head when he was in ihram.' "
He continued, "Abu Ayyub put his hand on the garment and pulled it down until I could see his head. He said to the man who was pouring out the water for him, 'Pour,' and he poured some over his head. Then he passed his hands over his head from the front to the back and then to the front again, and then said, 'I saw the Messenger of Allah ﷺ doing it like this.' "

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ إِبْرَاهِيمَ بْنِ عَبْدِ اللَّهِ بْنِ حُنَيْنٍ، عَنْ أَبِيهِ، أَنَّ عَبْدَ اللَّهِ بْنَ عَبَّاسٍ، وَالْمِسْوَرَ بْنَ مَخْرَمَةَ، اخْتَلَفَا بِالأَبْوَاءِ فَقَالَ عَبْدُ اللَّهِ يَغْسِلُ الْمُحْرِمُ رَأْسَهُ . وَقَالَ الْمِسْوَرُ بْنُ مَخْرَمَةَ لاَ يَغْسِلُ الْمُحْرِمُ رَأْسَهُ . قَالَ فَأَرْسَلَنِي عَبْدُ اللَّهِ بْنُ عَبَّاسٍ إِلَى أَبِي أَيُّوبَ الأَنْصَارِيِّ فَوَجَدْتُهُ يَغْتَسِلُ بَيْنَ الْقَرْنَيْنِ وَهُوَ يُسْتَرُ بِثَوْبٍ فَسَلَّمْتُ عَلَيْهِ فَقَالَ مَنْ هَذَا فَقُلْتُ أَنَا عَبْدُ اللَّهِ بْنُ حُنَيْنٍ أَرْسَلَنِي إِلَيْكَ عَبْدُ اللَّهِ بْنُ عَبَّاسٍ أَسْأَلُكَ كَيْفَ كَانَ رَسُولُ اللَّهِ ﷺ يَغْسِلُ رَأْسَهُ وَهُوَ مُحْرِمٌ قَالَ فَوَضَعَ أَبُو أَيُّوبَ يَدَهُ عَلَى الثَّوْبِ فَطَأْطَأَهُ حَتَّى بَدَا لِي رَأْسُهُ ثُمَّ قَالَ لإِنْسَانٍ يَصُبُّ عَلَيْهِ اصْبُبْ . فَصَبَّ عَلَى رَأْسِهِ ثُمَّ حَرَّكَ رَأْسَهُ بِيَدَيْهِ فَأَقْبَلَ بِهِمَا وَأَدْبَرَ ثُمَّ قَالَ هَكَذَا رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَفْعَلُ .