The Greatest Losers in respect of (Their) Deeds

Al-Bukhari recorded from `Amr that Mus`ab who said: "I asked my father -- meaning Sa`d bin Abi Waqqas -- about Allah's saying,

قُلْ هَلْ نُنَبِّئُكُم بِالاٌّخْسَرِينَ أَعْمَـلاً

The last sentence in the same verse (105): فَلَا نُقِيمُ لَهُمْ يَوْمَ الْقِيَامَةِ وَزْنًا (and We shall not assign to them any weight) means that their deeds may appear to be great outwardly, but when placed on the balance of reckoning, they will carry no weight. The reason is that these deeds will be of no use and will not carry any weight because of kufr (disbelief) and shirk (ascribing of partners to Allah).

According to a Hadith of Sayyidna Abu Hurairah ؓ appearing in the Sahih of al-Bukhari and Muslim, the Holy Prophet ﷺ said: On the day of Qiyamah, there will come a tall and heavy man who, in the sight of Allah, will not be worth the weight of a mosquito.' Then he said: 'If you wish to verify it, recite this verse of the Qur'an: فَلَا نُقِيمُ لَهُمْ يَوْمَ الْقِيَامَةِ وَزْنًا (and We shall not assign to them any weight).'