Ostentation is a serious sin. It indicates mental vices. The ostentatious do not have any relation with Allah. Islam has warned against exhibitionism and ordered Muslims of purifying themselves from its germs. The holy Quran, also, exposes and warns against ostentation. Allah says:

Surely, the hypocrites strive to deceive Allah, and He shall requite their deceit to them, and when they stand up to prayer, they stand up sluggishly. They do it only to be seen of men and do not remember Allah save a little.

Whoever hopes to meet his Lord, he should do good deeds, and not join any one in the service of his Lord.

Woe to the praying ones who are unmindful of their prayers, who do good to be seen and withhold the necessaries of life.

The reports that deal with and warn against the ostentation are uninterrupted.

The Prophet (s) said, “The most dangerous thing that I warn you against is the minor polytheism… It is the ostentation. On the Resurrection Day, Allah will say to the ostentatious: I reward the servants for their deeds. Go to those whom you were showing in the world. Will they reward you?”. “Allah will not admit any deed that possesses a bit of ostentation.”

Imam Ali (a) said, “Fear Allah exhaustively, and work for Him without seeking any reputation. He, whoever works for other than Allah, will be attached to those for whom he works.”.
Imam as-Sadiq (a) said, “Dedicate your affairs to Allah’s sake. Do not make them for people’s sake. Whatever is intended to Allah, goes to Allah, and whatever is intended to people will never ascend to Allah.”

Imam al-Rida (a) said, “You should work for other than ostentation or reputation. He, whoever works for other than Allah, will be attached to those for whom he works.

Ostentation is rebuked and considered as a sort of polytheism that never ascends to Allah. Incentives of ostentation:
 

Incentives of ostentation are as follows:

- Showing off piety and virtuousness for winning people’s respect and veneration.

- Showing off for holding some religious positions, the terms of which are piety and religiousness, such as judiciary and imamate,

- Showing off for winning people’s confidence, and planning for embezzling their trusts, or the like.
Only those who sacrifice the Hereafter for worldly affairs may take the path of ostentation. The ostentatious individuals, in fact, worship others besides Allah, and dress piety as a means of achieving the narrow aims.

Ostentation invalidates worship:

Muslim Jurists affirm unanimously that ostentation invalidates the worship. There is no difference in the rule whether such a state of ostentation occurs in the first of the ritual, in the middle or in any part of it. Likewise, ostentation invalidates the rites even if it is intended in some parts that are out of the obligatory ritual. For instance, the prayer is invalid when the performer shows off by joining a collective prayer, or choosing a definite mosque, imam, time or place.

The actual worship is engaged in the sincerity to Allah. When ostentation occurs, the rituals will be invalid and should be repeated.

Treatment of ostentation:

Ethicists mention a number of matters that eliminate this virulent defect.

- The ostentatious should clear the incentives of ostentation, such as the fondness of praise and greediness in people’s amenities.

- The ostentatious should regard the blights and calamities that are resulted from ostentation, such as the corruption of the deeds and Allah’s scorn.

- The ostentatious should consider that people’s praise and confidence would not improve the livelihood, since sustenance is Allah’s concern, and that whoever seeks sustenance from other than Allah will gain nothing but humility and decline.

- The ostentatious should concern the grief and the lack of tranquility that affect them because of presuming people’s emotions and trends. They should also remark that nothing would please people who have contradicting opinions and tendencies. This will surely bring about the most intolerable suffering and heartache and deprive of any profit.

- The ostentatious should consider that Allah will sooner or later divulge the ill intendments and unveil the actuality in this world or in the Hereafter. Thus, no profit is gained from the deceptive efforts. The ostentatious will surely get rid of their ill habits if they consider these treatments carefully.