Abdullah bin Abbas and Miswar bin Makhrama disagreed at al-Abwa.Abdullah bin Abbas said, "A person in the state of ihram may wash his head."Miswar said, "A person in the state of ihram may not wash his head."Ibn Abbas then sent me to Abu Ayub al-Ansari to ask him about this. I found him bathing between two posts, screened by a cloth. I greeted him, and he asked, "Who is this?"I replied, "I am Abdullah bin Hunayn. Abdullah bin Abbas has sent me to ask you how the Messenger of Allah ﷺ used to wash his head while in ihram."Abu Ayub placed his hand on the cloth and lowered it until his head became visible to me. Then he said to a man who was pouring water for him, "Pour."So the man poured water over his head. Abu Ayub then moved his head with his hands, bringing them forward and back, and said, "This is how I saw him ﷺ do it."
حدثنا أبو مصعب حدثنا مالك عن زيد بن أسلم
أن عبد الله بن عباس والمسور بن مخرمة اختلفا بالأبواء فقال عبد الله بن عباس يغسل المحرم رأسه وقال المسور لا يغسل المحرم رأسه فأرسلني ابن عباس إلى أبي أيوب الأنصاري أسأله عن ذلك فوجدته يغتسل بين القرنين وهو يستتر بثوب فسلمت عليه فقال من هذا قلت أنا عبد الله بن حنين أرسلني إليك عبد الله بن عباس أسألك كيف كان رسول الله ﷺ يغسل رأسه وهو محرم قال فوضع أبو أيوب يده على الثوب فطأطأه حتى بدا لي رأسه ثم قال لإنسان يصب عليه اصبب فصب على رأسه ثم حرك رأسه بيده فأقبل بهما وأدبر ثم قال هكذا رأيته ﷺ يفعل
Bukhari transmitted it in the Book of Hunting and Game, Chapter on Bathing for the One in Muharram Ihram, no. 1840, and Muslim in the Book of Hajj, Chapter on the Permissibility of the Muhrim Washing His Body and Head, no. 1205, from the hadith of Malik, by this route. It is also found in Muwatta (Yahya narration: 1/323, Abu Musab narration: 1/408-409, no. 1033), 1/408-409.