Amr bin Maymun said: I accompanied Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) for eighteen months, and I heard him narrate only a single hadith from the Messenger of Allah (peace and blessings be upon him), and he broke into a sweat. Then he said: "This, or something like it, or something resembling it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8584