Hadith 8:944
Abu Bakr narrated to us, he said: Abu Usama narrated to us, from Hisham, from al-Hasan, he said: He walks, and if he is cut off (prevented from completing the pilgrimage), he rides and offers a sacrificial camel.
حدثنا أبو بكر قال حدثنا أبو أسامة عن هشام عن الحسن قال يمشي فإن انقطع ركب وأهدى بدنة