Here are some Consequences of Ar-Riyya` (Showing off):
1- Ar-Riyya` is minor shirk – that does not remove one from Islaam – but it is shirk nonetheless, and therefore worse than bid’ah that does not reach the level of kufr, and also worse than major sins such as usury, sodomy, fornication, drinking alcohol, gambling… It can be major shirk, as Shaikh Muhammad ibn ‘Abdul-Wahhab al-Wasaabee (hafidhahullaah) explained while teaching al-Qawl-ul- Mufeed Fee Adillatit Tawheed: “Ar-Riyaa` (showing off) can be from ash-Shirk al-Akbar if a person performs an action only for the people. And it can be from ash-Shirk al-Asghar if a person starts with the right intention, but then ar-riyaa` overcomes him.”
Shaikh Rabee’ bin Haadee al-Madkhalee (hafidhahullaah), in his khutbah The Path to Guidance – as-Salafiyah – The Balanced Path, said: “There are two types of ar-Riyaa`: one that negates all of Tawheed, and one that negates the completeness of Tawheed.”
2- It nullifies the action. He will not receive a reward on the Day of Judgement for it.
3- Humiliation. Allaah will command him to go to those he showed off for in this world, and see if they have a reward for him. And as the scholars explained, Allaah will also expose this person in this world.
4- It may be a cause of entering the hellfire – aoodhubillaah! – even if it is not forever.
Ibn Taymeeyah (rahimahullaah) said: “Without doubt al-Ikhlaas negates the reason for entering into the Fire. Therefore, whoever enters the fire, from those who said: ‘La illaaha ila Allaah (there is none worthy of worship except Allaah),’ then this is proof that he never implemented the sincerity of La illaaha ila Allaah, which would have prohibited him from the fire. [al-Fataawa, 10/261]
5- It can lead to hypocrisy – aoodhubillaah! – since the hypocrites do deeds to be seen by men, while they disbelieve. And the hypocrites, of course, will be in the lowest level of the hellfire. Ibnul-Qayyim said: “If a benefit could be achieved from an action performed without Ikhlaas, then Allaah would not have criticised the hypocrites.” [al-Fawaa`id, 65]
And refuge in Allaah is taken from falling into ar-Riyya`, and that which ar-Riyya` may lead to.