(37) باب الْقَدَحِ فِي النَّوْمِ
Narrated `Abdullah bin `Umar:
I heard Allah's Messenger (ﷺ) saying, "While I was sleeping, I saw that a cup full of milk was brought to me and I drank of it and gave the remaining of it to `Umar bin Al-Khattab." They asked. What have you interpreted (about the dream)? O Allah's Messenger (ﷺ)?" The Prophet (ﷺ) said. "(It is Religious) knowledge."
Reference: Sahih al-Bukhari 7032
In-book reference: Book 91, Hadith 47
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 87, Hadith 157