Musnad Ahmad 3648

It was narrated that 'Abdullah bin Mas'ood (رضي الله عنه) said: The Messenger of Allah (ﷺ) said one day: “Feel shy before Allah in the true sense of the word.” We said: O Messenger of Allah, we do feel shy before Him, praise be to Allah. He said: "That is not what I meant. Rather the one who feels shy before Allah in the true sense of the word, let him guard his head and whatever is in it, guard his stomach and whatever it contains, and let him remember death and decay. Whoever seeks the Hereafter would give up the adornment of this world, and whoever does that has felt shy before Allah, may He be glorified and exalted, in the true sense of the word.”