"Those who exult in what they have done and love to be praised for what they have not done should not suppose that they have escaped the punishment. They will have a painful punishment.” (Surah Al-‘Imran, 188)

Pride in what they have done and of boasting about things that they in fact have not done may be a normal form of behavior for some people. But in this verse from Surat al-‘Imran, Allah reveals that this kind of behavior is not acceptable in His Sight.

Boasting is one of the main ways in which one’s earthly nature is nourished. Everyone has a reason for boasting about something he regards as being superior to other people, and one’s earthly nature delights in boasting. Underneath such behavior lie such perverse ideas as ascribing to one’s own earthly nature things that one imagines one does oneself but that actually come about as the result of Allah’s will and creation and praising one’s earthly nature because of these. Yet the fact is that whether a person does or does not do something himself, the one who is really deserving of praise is Omniscient and Almighty Allah, who creates whatever it is.

No human has any independent power of his own. Everything takes place by Allah’s leave and choosing. Our Lord merely tests His servants with the different superior attributes he bestows on them. Acting in the light of one’s earthly nature, being proud and delighting in being praised is behavior that will end up in loss. If someone with no independent power to do anything becomes proud and boasts of something he lacks the power to do, that shows that he is unable to properly appreciate Allah, he who really creates all attributes. And this is equivalent to ascribing divine status to one’s earthly nature (surely Allah is beyond that) and adopting one’s earthly nature as an equal to Allah. Allah reveals in the Qur’an that ascribing equals to Him is the greatest sin, and that He will not forgive anyone who does this unless they repent. These verses say those who praise themselves instead of the limitless might of our Lord  will receive a terrible punishment.