Narrated `Abdullah bin `Umar:I heard Allah's Messenger (ﷺ) saying, "While I was sleeping, I saw a bowl full of milk was brought to me and I drank of it (to my fill) till I noticed its wetness flowing (in my body). Then I gave the remaining of it to `Umar." They asked, "O Allah's Messenger (ﷺ)! What have you interpreted (about the dream)? He said, "(It is Religious) knowledge." (See Hadith No)
Hadith No. 7027
Sahih al Bukhari