The Book of Purification
Bulugh al-Maram #70
كتاب الطهارة
وَعَنْ عَلِيٍّ - رضى الله عنه - قَالَ: «لَوْ كَانَ اَلدِّينُ بِالرَّأْيِ لَكَانَ أَسْفَلُ اَلْخُفِّ أَوْلَى بِالْمَسْحِ مِنْ أَعْلَاهُ, وَقَدْ رَأَيْتُ رَسُولَ اَللَّهِ - صلى الله عليه وسلم -يَمْسَحُ عَلَى ظَاهِرِ خُفَّيْهِ» أَخْرَجَهُ أَبُو دَاوُدَ بِإِسْنَادٍ حَسَنٍ
Narrated ‘Ali (rad):
If the religion were based on opinion, it would be more important to wipe over the under parts of the leather socks than the upper, but I have seen Allah’s Messenger (rad) wiping over the upper parts of his leather socks. .
وَعَنْ عَلِيٍّ - رضى الله عنه - قَالَ: "لَوْ كَانَ اَلدِّينُ بِالرَّأْيِ لَكَانَ أَسْفَلُ اَلْخُفِّ أَوْلَى بِالْمَسْحِ مِنْ أَعْلَاهُ, وَقَدْ رَأَيْتُ رَسُولَ اَللَّهِ - صلى الله عليه وسلم -يَمْسَحُ عَلَى ظَاهِرِ خُفَّيْهِ" أَخْرَجَهُ أَبُو دَاوُدَ بِإِسْنَادٍ حَسَنٍ
If the religion were based on opinion, it would be more important to wipe over the under parts of the leather socks than the upper, but I have seen Allah’s Messenger (rad) wiping over the upper parts of his leather socks. .
— Bulugh al-Maram, Hadith 70