“I always preferred to wash the under part of the feet until I saw the Messenger of Allah ﷺ wiping the upper part of them.
مَا كُنْتُ أُرَى بَاطِنَ الْقَدَمَيْنِ إِلاَّ أَحَقَّ بِالْغَسْلِ حَتَّى رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَمْسَحُ عَلَى ظَهْرِ خُفَّيْهِ