Abu Asma', the freed slave of Abdullah bin Ja'far (may Allah be pleased with him), related that he was with Abdullah bin Ja'far (may Allah be pleased with him) and set out with him from Madinah. They passed by Sayyiduna Husayn bin Ali (may Allah be pleased with him), who was ill at al-Suqya. Abdullah bin Ja'far (may Allah be pleased with him) stayed with him until, when he feared missing (the Hajj), he left, and sent word to Sayyiduna Ali bin Abi Talib and Sayyidah Asma' bint Umays (may Allah be pleased with them both), who were in Madinah at that time, and they both came to him. Then Sayyiduna Husayn (may Allah be pleased with him) pointed to his head, so Sayyiduna Ali (may Allah be pleased with him) ordered that his head be shaved; then he offered a sacrifice on his behalf at al-Suqya, slaughtering a camel for him. Yahya said: Sayyiduna Husayn (may Allah be pleased with him) had set out with Sayyiduna Uthman bin Affan (may Allah be pleased with him) on that journey of his.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10088