"The Messenger of Allah passed by an old man who was being supported between two men and said: 'What is the matter with him?' They said: 'He vowed to walk.' He said: 'Allah has no need for him to torture himself. Tell him to ride.'" So he was told to ride.
مَرَّ رَسُولُ اللَّهِ ﷺ بِشَيْخٍ يُهَادَى بَيْنَ اثْنَيْنِ فَقَالَ مَا بَالُ هَذَا قَالُوا نَذَرَ أَنْ يَمْشِيَ قَالَ إِنَّ اللَّهَ غَنِيٌّ عَنْ تَعْذِيبِ هَذَا نَفْسَهُ مُرْهُ فَلْيَرْكَبْ فَأَمَرَهُ أَنْ يَرْكَبَ