Ibn 'Umar narrated that the Messenger of Allah (s.a.w) said:
"While I was sleeping , I was brought a cup of milk and I drank from it. Then I gave what I had left to 'Umar bin Al-Khattab." They said; "How did you interpret it O Messenger of Allah?" He said: "Knowledge." (ES)
English reference (ES): Vol. 4, Book 8, Hadith 2284 (ES)
Arabic reference (ES): Book 34, Hadith 2453 (ES)