Chapter 1: The Book of the Sunnah
Amr bin Maimun said: "I used to visit Ibn Mas' ud every Thursday afternoon but he never uttered the words: 'The Messenger of Allah (ﷺ) said.' Then one evening, he said: 'The Messenger of Allah (ﷺ) said,' then he let his head hang down." He said: "I looked at him and saw his shirt was unfastened; his eyes were filled with tears, and his veins were bulging out (with fear). He said: 'Or more than that, or less than that, or close to that or something similar.'"
Sunan Ibn Majah 23