Mukhtasar Bukhari

Narrated from Sayyiduna Anas (may Allah be pleased with him) that the Prophet Muhammad (peace and blessings be upon him) saw an old man being led between his two sons. The Prophet (peace be upon him) asked: "What has happened to him?" The people replied that he had vowed to go on foot. The Prophet (peace be upon him) said: "Allah is not in need of him punishing himself." And he ordered the old man to ride.