Ubadah bin Nusayy said: I went to Sayyiduna Shaddad bin Aws (may Allah be pleased with him) at his place of prayer, and he was weeping. I asked: O Abu Abd al-Rahman! What has made you weep? He said: A hadith that I heard from the Messenger of Allah (peace and blessings be upon him). I said: What is it? He said: Once I was with the Messenger of Allah (peace and blessings be upon him) when I saw on his blessed face a look that saddened me. I said: May my father and mother be sacrificed for you, O Messenger of Allah! What is this that I see on your blessed face? He (peace and blessings be upon him) said: "A matter that I fear for my Ummah after me." I said: What is it? He (peace and blessings be upon him) said: "Shirk and a hidden desire (of the self)." I said: O Messenger of Allah! Will your Ummah commit shirk after you? He (peace and blessings be upon him) said: "O Shaddad! Behold, they will not worship the sun, an idol or a stone, but they will show off their deeds to people." I said: O Messenger of Allah! Is showing off (riya') shirk? He (peace and blessings be upon him) said: "Yes." I said: And what is the hidden desire? He (peace and blessings be upon him) said: "One of you begins the day fasting (a voluntary fast), then one of the desires of this world presents itself to him, and he breaks his fast (without excuse)." This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.