حَدَّثَنِي حَرْمَلَةُ بْنُ يَحْيَى، أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، أَنَّ ابْنَ شِهَابٍ، أَخْبَرَهُ عَنْ حَمْزَةَ بْنِ عَبْدِ اللَّهِ بْنِ عُمَرَ بْنِ الْخَطَّابِ، عَنْ أَبِيهِ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ بَيْنَا أَنَا نَائِمٌ إِذْ رَأَيْتُ قَدَحًا أُتِيتُ بِهِ فِيهِ لَبَنٌ فَشَرِبْتُ مِنْهُ حَتَّى إِنِّي لأَرَى الرِّيَّ يَجْرِي فِي أَظْفَارِي ثُمَّ أَعْطَيْتُ فَضْلِي عُمَرَ بْنَ الْخَطَّابِ ‏"‏ ‏.‏ قَالُوا فَمَا أَوَّلْتَ ذَلِكَ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ الْعِلْمَ ‏"‏ ‏.‏

Hamza b. Abdullah b. 'Umar b. Khattab reported on the authority of his father that Allah's Messenger (PBUH) said: While I was asleep I saw (in a dream) a cup containing milk being presented to me. I took out of that until I perceived freshness being reflected through my nails. Then I presented the leftover to 'Umar b. Khattab. They said: Allah's Messenger: How do you interpret it? He said: This implies knowledge. Translation Not Available

Book Ref: Sahih Muslim Book 44 Hadith 5888
Web Ref:  Sahih Muslim Book 31 Hadith 2391 a