Allah, the Wise, has said:
وَ لاَ تَکُونُوا کَالَّذِينَ خَرَجُوا مِنْ دِياَرِکُم بَطَراً وَ رِئاَءَ النَّاسِ
"And be not like those who came forth from their homes in great exultation and to be sin of men." 
The Noble Prophet (s.a.w) said:
لاَ يَقْبَلُ اللهُ تَعاَلىَ عَمَلاً فِيهِ مِثقاَلُ ذَرَّةٍ مِنْ رِياَءٍ
"Allah shall not accept a deed, which has an atom's weight of showing off in it." 
Showing off is a tree that comes into existence as a result of hypocrisy and whose fruit is nothing but concealed polytheism. It is exhibited before entities that neither have the ability to grant life and death, nor the authority to fulfil the needs of any person.
On the Day of Judgment, at the time of reckoning, it will be said to a person who showed off: "Collect the rewards of your deeds from those, whom you had made partners to Me and for whom you had performed your deeds!!"
Showing off usually occurs in gatherings and with respect to clothes and acts of worship. Thus, it is essential to remain attentive towards and heedful of Allah in order to purge our interiors of this satanic vice.
1 – The Proud Monk
Ibrahim Adham narrated: "I acquired wisdom and enlightenment from a monk by the name of Samaan. One day I entered his monastery and asked him: "O' Samaan! How long have you been in this monastery?" He replied: "Seventy years." I inquired: "What has been your food during this period?" He asked: "Why do you ask such a question?" I said: "I am curious to know." He said: "Every night I eat just one hazel-nut!" I inquired: "What is it that keeps your mind so engrossed so as to make one hazel-nut sufficient for you?"
He replied: "Every year on an appointed day, a group of my followers come here, revere me, decorate the monastery, circumembulate it and then depart. Whenever I get exhausted of worship and experience hunger and loneliness, I overcome it by bringing to mind that day, and the honour and esteem that I come to acquire in it. Thus, my entire year's exertion and efforts are motivated by the grandeur of that one day!'
2 – The Congregational Prayers
One of the distinguished scholars, who had journeyed the path of spiritual cleansing and possessed sublime ethics, was Mulla Abdullah Shushtari. He was the tutor of Muhammad Taqi Majlisi and has numerous books to his name, one of them being Majame' al-Fawaid, which runs into seven volumes.
He was a contemporary of Sheikh Baha`i and one day, proceeded to pay him a visit. They sat in conversation until the sound of adhan was heard whereupon Sheikh Baha`i said to him: "Offer your prayers here so that we can follow you and acquire the rewards of the congregational prayers."
Mulla reflected for a few moments after which, excusing himself, he got up and left for his house. He was (later) asked: "Why did you turn down the Sheikh's offer when you yourself attach great importance to offering the prayers as soon as its time sets in?"
He replied: "I reflected within myself and perceived that I was not of the kind that if a person like Sheikh were to pray behind me, I would not experience a change of state. I realized that some form of showing off might creep into me and so turned down his request."
3 – The Two Apparels
Sufiyan Thauri happened to pass by Masjid al-Haram and there he witnessed Imam Sadiq (a.s) wearing costly and expensive clothes. He said to himself: "By Allah! I shall go to him and reprimand him."
Approaching the Imam (a.s), he said: "O' Son of the Prophet of Allah! By Allah! You have attired yourself in a clothing, the like of which had neither been worn by the Noble Prophet (s.a.w) nor by Ali (a.s) or any of your fore-fathers!"
Hearing this, the Imam (a.s) said: "During the era of the Noble Prophet (s.a.w), the people were troubled with poverty and paucity, but later the circumstances improved and things changed for the better. (Do know!) Of the inhabitants of the world those, who most deserve to taste the benefits of Abundance, ease and comfort, are the righteous ones."
Having said this he (a.s) recited the following verse, "Say: Who has prohibited the embellishment of Allah which He has brought forth for His servants and the good provisions?"
And then said: "Thus, we are the ones, who most deserve to utilize that which Allah has provided. O' Sufiyan! The apparel that you presently observe me wearing is for the people and for preserving my reputation and esteem."
Then, taking hold of Sufiyan's hand, the Imam drew back his dress, revealing his inner clothing which was coarse and rough. He then said: 'This, I have worn for myself while the other I have worn for the people.'
Then, taking hold of Sufiyan's clothing, he (a.s) pulled it up to reveal a soft inner clothing and said: 'You have worn this (simple) exterior clothing for the people and the concealed soft inner clothing for your ease and comfort!'
4 – The Dissembled Worship
There once lived a worshipper who could never get himself to perform any of his deeds sincerely, and free from showing off.
Once, attempting to redress his problem, he said to himself: 'In the corner of the city there lies an abandoned mosque which is never frequented by anyone. It would be better if I go there in the night so that there is none to see me, and engage myself in worshipping Allah, in total sincerity.'
At midnight, in the darkness of the night, he stealthily set out for the mosque. The night was a rainy one with severe lightening and thunder.
Once inside, he engaged himself in worship. A short while later he suddenly happened to hear a sound and ecstatically said to himself: 'Surely, a person has entered the mosque.' With this in mind he increased the quality and quantity of his prayers and continued his acts of worship till daybreak. In the morning, as he was about to go out of the mosque, he looked behind with the corner of his eyes only to realize that there was no one there save a black dog that had sought shelter in the mosque from the rains, lightning and thunder.
This distressed him immensely, and repentant and shameful for having worshipped for hours for a dog, he rebuked himself: 'Woe unto me! I fled and came to this abandoned mosque so that I could worship Allah with sincerity, but I have ended up performing my acts of worship for a black dog, instead.'
5 – Informing People of Worship
In the tribe of Bani Isra`il, there lived a worshipper who after years of worship, requested Allah to manifest to him his rank and status, and prayed: 'O' Lord! If my deeds are to Your liking, I would strive further in performing good deeds, but if not, then I would want to make amends for it before death overtakes me, and engage myself (more) in acts of worship.'
In his dreams he was informed: 'In the eyes of Allah, you do not possess any good deed.' Perturbed, he exclaimed: 'O' Allah! Where then have my deeds gone?' It was said to him: 'You do not possess any deed, for whenever you performed a good did, you informed the people of it. Therefore, the pleasure that you derived out of informing them of your acts is your reward for those acts.' This disturbed him immensely and left him greatly saddened.
For the second time, he was informed in his dreams: 'Now purchase your life from Us. Give charity equivalent to the number of veins in your body, every day!'
He pleaded: 'O' Lord! How can I give such a large amount in charity when I do not possess anything?'
He heard: 'We do not impose any duty on a soul except in the measure of its ability. Recite the following three hundred and sixty times daily; every word of it is charity for a vein of your body:
سُبْحَانَ 9للٌّهِ وَ الْحَمْدُ لِلٌّهِ وَ لاٌ إِلٌهَ إِلاَّ 9للٌّهُ وَ 9للٌّهُ أَكْبَرُ وَ لاٌ حَوْلَ وَ لاٌ قُوَّةَ إِلاَّ بِاللٌّهِ
Subhan Allahi, Wal Hamdu Lillahi, Wa La Ilaha Illallahu, Wallahu Akbar, Wa La Haul Wa La Quwwata Illa Billah.'
The worshipper, who was overjoyed to hear these words, said: 'Grant me more than this', whereupon it was said to him: 'The more you recite the more reward you shall earn.')
 Suratul Anfal (8), vol. 47
 Jami~ al-Sa~adat, vol. 2, pg. 376
 Tadhkeratul Haqa`iq, pg. 48
 Shanidaniha-e-Tarikh, pg. 362, Mahajjatul Baidha, vol. 6, pg. 207
 Qasas al-~Ulama, pg. 336
 Sima-e-Farzanegan, pg. 147; Bidadgaran-e-Aqalim-e-Qiblah, pg. 14
 Suratul A~raf (7), Verse 32
 Ba Mardum In Guneh Barkhord Konim, pg. 169; Bihar al-Anwar, vol. 47, pg. 360
 Dastan-ha Wa Pand-ha, vol. 9, pg. 173; Muntakhab Qawamis al-Durar, pg. 144
 Pand-e-Tarikh, vol. 1, pg. 35; Bihar al-Anwar, vol. 18, pg. 523 (Old Publication