It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him): I was not kept back from three things, namely confidential talk and such-and-such matters (of attendance upon the Messenger of Allah (peace and blessings be upon him)). I came to him (peace and blessings be upon him), and Malik bin Murarah al-Rahawi was there. I caught the last part of what he was saying; he was saying: "O Messenger of Allah, I have been given of beauty what you see, and I do not like anyone to surpass me even in the strap of my sandal. Is this transgression?" He (peace and blessings be upon him) said: "This is not transgression; rather, transgression (arrogance) is rejecting the truth and looking down on people." This hadith is sahih al-isnad (its chain is authentic), but the two Shaykhs (Bukhari and Muslim) did not record it.