Sunan al-Shafi'i

It is narrated from Abdullah bin Haneen (may Allah have mercy on him) that there was a disagreement between Sayyiduna Ibn Abbas (may Allah be pleased with them both) and Miswar bin Makhramah (may Allah be pleased with him) at Abwa regarding whether a Muhrim (one in the state of Ihram) can wash his head. Ibn Abbas (may Allah be pleased with them both) said that a Muhrim can wash his head, while Miswar (may Allah be pleased with him) said he cannot. So Sayyiduna Ibn Abbas (may Allah be pleased with them both) sent me to Sayyiduna Abu Ayyub Ansari (may Allah be pleased with him) to ask about the issue. I found him bathing between two wooden planks of a well, having covered himself with a cloth. I greeted him with Salam, so he said, "Who is it?" I said, "I am Abdullah bin Haneen (may Allah have mercy on him); Ibn Abbas (may Allah be pleased with them both) has sent me to ask how the Messenger of Allah ﷺ used to wash his head (while in the state of Ihram)." So Abu Ayyub (may Allah be pleased with him) lowered the cloth a little with his hand until his head became visible to me, then he said to the person pouring water over him, "Brother, pour water." He poured water over his head, then he rubbed his head with both hands, first moving both hands forward, then bringing them back, and said: "I saw the Messenger of Allah ﷺ doing it like this."