Muwatta Imam Malik Book of Dress, Hadith 12
Yahya related to me from Malik from al Ala ibn Abd ar-Rahman that his father said, "I asked Abu Said al-Khudri about the lower garment. He said that he would inform me with knowledge and that he had heard the Messenger of Allah ﷺ say, 'The lower garment of the mumin should reach to the middle of his calves. There is no harm in what is between that and the ankles. What is lower than that is in the Fire. What is lower than that is in the Fire. On the Day of Rising, Allah will not look at a person who trails his lower garment in arrogance.' "
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ الْعَلاَءِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِيهِ، أَنَّهُ قَالَ سَأَلْتُ أَبَا سَعِيدٍ الْخُدْرِيَّ عَنِ الإِزَارِ، فَقَالَ أَنَا أُخْبِرُكَ بِعِلْمٍ، سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ " إِزْرَةُ الْمُؤْمِنِ إِلَى أَنْصَافِ سَاقَيْهِ لاَ جُنَاحَ عَلَيْهِ فِيمَا بَيْنَهُ وَبَيْنَ الْكَعْبَيْنِ مَا أَسْفَلَ مِنْ ذَلِكَ فَفِي النَّارِ مَا أَسْفَلَ مِنْ ذَلِكَ فَفِي النَّارِ لاَ يَنْظُرُ اللَّهُ يَوْمَ الْقِيَامَةِ إِلَى مَنْ جَرَّ إِزَارَهُ بَطَرًا " .