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: Messenger of Allah: How do you interpret it? He said: This implies knowledge. (Using translation from Muslim 2391a)
كَانَ رَسُولُ اللهِ ﷺ يُحَدِّثُ قَالَ بَيْنَا أَنَا نَائِمٌ رَأَيْتُنِي أُتِيتُ بِقَدَحِ [لَبَنٍ] فَشَرِبْتُ مِنْهُ حَتَّى إِنِّي أَرَى الرِّيَّ يَخْرُجُ في أَطْرَافِي ثُمَّ أَعْطَيْتُ فَضْلِي عُمَرَ بْنَ الْخَطَّابِ فَقَالُوا فَمَا أَوَّلْتَ ذَلِكَ يَا رَسُولَ اللهِ؟ قَالَ الْعِلْمُ