(9) باب تَحْرِيمِ جَرِّ الثَّوْبِ خُيَلاَءَ وَبَيَانِ حَدِّ مَا يَجُوزُ إِرْخَاؤُهُ إِلَيْهِ وَمَا يُسْتَحَبّ
Ibn 'Umar reported:
I happened to pass before Allah's Messenger (may peace be upon bin) with my lower garment trailing (upon the ground). He said: 'Abdullah, tug up your lower garment,, I tugged it up, and he again said: Tug it still further, and I tugged it still further and I went on tugging it afterward, whereupon some of the people said: To what extent? Thereupon he said: To the middle of the shanks.
Reference: Sahih Muslim 2086
In-book reference: Book 37, Hadith 77
USC-MSA web (English) reference(deprecated numbering scheme): Book 24, Hadith 5200