Sunan an-Nasa'i, Book 47, Hadith 27 (In-Book) ⓘ
Abu Sa'eed Al-Khudri said: "The Messenger of Allah [SAW] said: 'While I was sleeping, I saw the people being shown to me, and they were wearing shirts. Some reached the breast and some reached lower than that. And 'Umar bin Al-Khattab was shown to me, and he was wearing a shirt that he was dragging;' They said: 'How do you interpret that, O Messenger of Allah?' He said: 'The religion.'"
أَخْبَرَنَا مُحَمَّدُ بْنُ يَحْيَى بْنِ عَبْدِ اللَّهِ قَالَ حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ بْنِ سَعْدٍ قَالَ حَدَّثَنَا أَبِي عَنْ صَالِحِ بْنِ كَيْسَانَ عَنْ ابْنِ شِهَابٍ قَالَ حَدَّثَنِي أَبُو أُمَامَةَ بْنُ سَهْلٍ أَنَّهُ سَمِعَ أَبَا سَعِيدٍ الْخُدْرِيَّ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بَيْنَا أَنَا نَائِمٌ رَأَيْتُ النَّاسَ يُعْرَضُونَ عَلَيَّ وَعَلَيْهِمْ قُمُصٌ مِنْهَا مَا يَبْلُغُ الثُّدِيَّ وَمِنْهَا مَا يَبْلُغُ دُونَ ذَلِكَ وَعُرِضَ عَلَيَّ عُمَرُ بْنُ الْخَطَّابِ وَعَلَيْهِ قَمِيصٌ يَجُرُّهُ قَالَ فَمَاذَا أَوَّلْتَ ذَلِكَ يَا رَسُولَ اللَّهِ قَالَ الدِّينَ
also referenced under: Hadith 5011 (Reference) & Volume 6, Book 47, Hadith 5014 (DarusSalam)