Who are those referred to as: الْأَخْسَرِينَ أَعْمَالًا (The greatest losers in respect of [ their ] deeds - 103)? At this place, the first two verses (101, 102) are, in terms of their general sense, inclusive of every individual or group that would put in a lot of effort in some deeds taking them to be good, but with Allah their effort is ruined and their deed, wasted. Al-Qurtubi said that this situation is caused due to two things. One: Corruption in Belief. Two: Hypocrisy. It means that a person whose very Belief and Faith is not correct - no matter how good he is in his deeds and how painstaking in his effort - will find all this useless and wasted in the Hereafter.
Similarly, the deed of anyone who acts for the pleasure of the created by way of hypocrisy, that deed too will remain deprived of thawab (reward). It is in terms of this general sense that some revered Sahabah have declared the Kharjites as the substantiation of this verse. Then, there are some commentators who take the Mu'tazilah, the Rawafid and some others as the groups who have strayed away from the straight path. But, in the next verse (105), it has been determined that meant at this place are those particular disbelievers who deny the verses of Allah Ta’ ala and the coming of Qiyamah and Akhirah. It was said: الَّذِينَ كَفَرُوا بِآيَاتِ رَبِّهِمْ وَلِقَائِهِ (Those are the ones who disbelieved in the signs of their Lord and in the meeting with Him). Therefore, al-Qurtubi, Abu Hayyan, Mazhari and others prefer the view that really meant at this place are particular disbelievers who deny Allah, the Last Day and the Reckoning of deeds. But, apparently too, even those people whose deeds were ruined by their corrupted beliefs and whose effort had gone waste cannot remain unaffected by its general sense. As for the related sayings re-ported from Sayyidna ` Ali and Sa` d ؓ ، this is precisely what they mean. (Qurtubi)