قَالَ أَحْمَدُ: لَا يَثْبُتُ فِيهِ شَيْء ٌ 1‏ .‏‏1 ‏- كما في "مسائل ابن هانيء" (1/16/3)‏.‏ قلت: ولكن الحديث حسن بشواهده، وصححه غير واحد من الحافظ، وقد فصلت القول فيه في "الأصل".‏
Translation
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. [Reported by Abu Da’ud with good Isnad (chain of narrators)].