Jami` at-Tirmidhi, Volume 6, Book 46, Hadith 3687 (DarusSalam) ⓘ
Narrated Ibn 'Umar: "The Messenger of Allah said: 'I saw that I was brought a cup of milk, so I drank from it, and I gave my leftover to 'Umar bin Al-Khattab.' They said: 'So what did you interpret it as O Messenger of Allah?' He said: '(It is) Knowledge.'"
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ الزُّهْرِيِّ، عَنْ حَمْزَةَ بْنِ عَبْدِ اللَّهِ بْنِ عُمَرَ، عَنِ ابْنِ عُمَرَ، رضى الله عنهما قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " رَأَيْتُ كَأَنِّي أُتِيتُ بِقَدَحٍ مِنْ لَبَنٍ فَشَرِبْتُ مِنْهُ فَأَعْطَيْتُ فَضْلِي عُمَرَ بْنَ الْخَطَّابِ " . قَالُوا فَمَا أَوَّلْتَهُ يَا رَسُولَ اللَّهِ قَالَ " الْعِلْمَ " . قَالَ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ غَرِيبٌ .
also referenced under: Hadith 3687 (Reference) & Book 49, Hadith 4051 (In-Book)