Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) saw lice falling on his face. He (peace and blessings be upon him) asked: "Are these lice troubling you?" He said: Yes. He (peace and blessings be upon him) ordered: "Shave your head." They were at al-Hudaybiyah, and it had not been made clear that they would leave ihram there, for they were hoping to enter Makkah. Allah revealed this verse: "Then a ransom of fasting or charity or sacrifice" [Surah al-Baqarah: 196], that is, the ransom is fasting, charity or a sacrifice: one faraq (of food) among six needy people, or the sacrifice of a goat, and that is to be in Makkah.
(b) In the hadith of Shibl, the words «al-nusuk bi-Makkah» (the sacrifice is at Makkah) are not present.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9901