عَنِ ابْنِ عُمَرَ قَالَ: رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَلْبَسُ النِّعَالَ الَّتِي ليسَ فِيهَا شعرٌ. رَوَاهُ البُخَارِيّ

He reported God’s messenger as saying, “None of you should walk with one sandal, but should walk barefoot or wear a pair.” (Bukhari and Muslim.)