Sahih al-Bukhari, Hadith 3691 ⓘ
Narrated Abu Sa`id Al-Khudri: I heard Allah's Messenger saying, "While I was sleeping, the people were presented to me (in a dream). They were wearing shirts, some of which were merely covering their (chests). and some were a bit longer. `Umar was presented before me and his shirt was so long that he was dragging it." They asked, "How have you interpreted it, O Allah's Messenger?" He said, "Religion."
حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي أَبُو أُمَامَةَ بْنُ سَهْلِ بْنِ حُنَيْفٍ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ ـ رضى الله عنه ـ قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " بَيْنَا أَنَا نَائِمٌ رَأَيْتُ النَّاسَ عُرِضُوا عَلَىَّ وَعَلَيْهِمْ قُمُصٌ، فَمِنْهَا مَا يَبْلُغُ الثَّدْىَ، وَمِنْهَا مَا يَبْلُغُ دُونَ ذَلِكَ، وَعُرِضَ عَلَىَّ عُمَرُ وَعَلَيْهِ قَمِيصٌ اجْتَرَّهُ ". قَالُوا فَمَا أَوَّلْتَهُ يَا رَسُولَ اللَّهِ قَالَ " الدِّينَ ".
also referenced under: Book 62, Hadith 42 (In-Book) & Volume 5, Book 57, Hadith 40 (USC-MSA)