Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: "By Allah, I think that if the knowledge of Umar (may Allah be pleased with him) were placed in one pan of the scale, and the knowledge of all the living people on earth were placed in the other pan, the knowledge of Umar (may Allah be pleased with him) would outweigh it." Sulayman (al-A'mash) said: I mentioned this (to someone), and he said: "Sayyiduna Abdullah (may Allah be pleased with him) said something even greater than that. He said: 'I think that Umar (may Allah be pleased with him) took nine-tenths of knowledge with him.'"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8776