The Prophet ﷺ passed by a very old man who was being supported as he walked between his two sons. He asked, "What is the matter with this man?"They said, "Messenger of Allah, he vowed to walk."He said, "Allah has no need for this man to torment himself." So he ordered him to ride.Muhammad bin Muthanna reported to us that Ibn Abu Adi related from Humayd, from Anas, that the Messenger of Allah ﷺ saw a man, and he mentioned something similar. This hadith is authentic.
حدثنا أبو موسى محمد بن المثنى حدثنا خالد بن الحارث حدثنا حميد عن ثابت
مر النبي ﷺ بشيخ كبير يتهادى بين ابنيه فقال ما بال هذا قالوا يا رسول الله نذر أن يمشي قال إن الله عز وجل لغني عن تعذيب هذا نفسه قال فأمره أن يركب حدثنا محمد بن المثنى حدثنا ابن أبي عدي عن حميد عن أنس أن رسول الله ﷺ رأى رجلا فذكر نحوه هذا حديث صحيح
[Sahih]. Nasai also recorded it: 30/7, no. 3884 (Oaths and Vows, chapter on what is obligatory upon one who imposes a vow on himself and then becomes unable to fulfill it), from Muhammad bin Muthanna, through the same chain. Bukhari also narrated it, no. 1865, and Muslim, no. 1642, from the hadith of Humayd Tawil, through the same chain. And the hadith of Humayd from Anas is found in Nasai, no. 3885.