Imran bin Husayn (may Allah be pleased with him) said: Whenever the Prophet (peace and blessings be upon him) sat among us, he would either encourage us to give charity or forbid us from muthlah (mutilation), and he said: "Mutilation is that you pierce your nose or perform Hajj on foot. When a vow is made to perform Hajj on foot, then offer a sacrifice in exchange for it and ride."
(b) In the hadith of Salih: He should offer a camel in sacrifice and choose to ride.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النذور / 20125