عن محمود بن لبيد رضي الله عنه مرفوعاً: "أَخْوَفُ ما أخاف عليكم: الشرك الأصغر، فسئل عنه، فقال: الرياء". [صحيح] - [رواه أحمد] المزيــد ...
Mahmūd ibn Labīd (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: ''The thing that I fear most for you is minor polytheism.'' When asked what it was, he said: ''Riyā’." Sahih/Authentic. - [Ahmad]
The Prophet (may Allah's peace and blessings be upon him) tells us in this Hadīth that he fears for us, and that the thing he fears for us most is the minor polytheism which is Riyā', which means doing good deeds to show off before people, rather than having a sincere intention to earn Allah's pleasure and reward. There are many and strong motives for Riyā’, so it is possible that a Muslim commits Riyā’ without being aware that he is doing so. Therefore, the Prophet warned Muslims against it, out of perfect compassion for them and concern for their best interests.
Showing off is more dangerous for pious people than the trial of the Anti-Christ.
We should beware of show-off and polytheism in general.
It shows the Prophet’s great compassion toward his Ummah and his keenness to guide and advise them (may Allah’s peace and blessings be upon him).
Polytheism is divided into major and minor. Major polytheism is to set up an equal to Allah Almighty with regard to any of the traits exclusive to Him. Minor polytheism, on the other hand, is anything described in the religious texts as polytheism yet it does not reach the degree of the major one. The difference between the two is that: 1) major polytheism renders all deeds worthless whereas minor polytheism only ruins the deeds associated with it; 2) major polytheism causes one to eternally dwell in Hellfire whereas minor polytheism does not entail eternal stay in Hellfire; 3) major polytheism brings its perpetrator out of the fold of Islam while the minor one does not.