Musnad Abu Ya'la al-Mawsili 152:223

Abu Khaythama narrated to us, Yazid bin Harun narrated to us, Ibn 'Awn narrated to us, from 'Amr bin Sa'id, from Humayd bin 'Abd al-Rahman al-Himyari, from 'Abdullah bin Mas'ud, who said: "I was not prevented from three, or I was not held back from three—regarding private conversation, and such and such, and such and such." 'Abdullah said: "My uncle forgot one, and I forgot the other, and this one remained." So I came to him while Malik al-Ruhawi was with him, and I caught the end of their conversation, and he was saying: "O Messenger of Allah, I am a man who has been allotted the beauty that you see, and I do not like that anyone should excel me by even two sandal straps or more. Is this considered insolence (al-baghy)?" He said: "No, but insolence is rejecting the truth and looking down upon people."