أَنزَلۡنَآ إِلَيۡكَ ٱلۡڪِتَـٰبَ بِٱلۡحَقِّ فَٱعۡبُدِ ٱللَّهَ مُخۡلِصً۬ا لَّهُ ٱلدِّينَ
Verily, We have sent down the Book to you (O Muhammad SAW) in truth: So worship Allâh (Alone) by doing religious deeds sincerely for Allâh’s sake only.
[Surah az-Zumar (39): 2]
Imam Sufyaan at-Thawri once wrote in a letter to one of his Brothers:
“….Beware of doing that which will spoil your deeds, and know that it is showing off that spoils a person’s deeds; and if it is not showing off then it is conceitedness- for you to imagine that you are better than one of your Muslim brothers, when in reality he performs more good deeds than you do; or perhaps he stays further away from that which Allah has prohibited than you do; or perhaps he performs his deeds with purer intention that you do. And even if you are not conceited, beware of developing a love for praise. Be ever so careful not to come to love other people’s praise of your good deeds, or the respect they feel for you and bestow upon you because of your good deeds. And beware of desiring that others should help you in your personal affairs just because they have become impressed by your good deeds. You surely claim (as does everyone else), after all, that you are doing good deeds only for the sake of Allah, well, then turn that claim into reality….”
Source: Biography of Imam Sufyaan ath-Thawri by Salaahud-Deen ibn Ali ibn Abdul-Maujood
The Messenger of Allah (صلى الله عليه وسلم) said:
“Whoever shows off, Allaah will expose him.”
(Narrated by al-Bukhaari, 6134; Muslim; 2986).
Ibn Hajar said: al-Khattaabi said, this means: whoever does something that is not sincerely for the sake of Allaah, merely wanting people to see him and hear him, will be punished for that – Allaah will expose him and make known what he is concealing.
It was said that whoever does something with the intention of gaining status and prestige among people, and does not seek the Face of Allaah by doing it, Allaah will make him the subject of bad speech among the people in whose eyes he wanted to gain status, and he will have no reward for it in the Hereafter.
(Fath al-Baari, 11/336)