The word الْحَاقَّةُ refers to something which is bound to happen as per the dictates of common sense and morality; something which is inevitable and certain to materialize. This one word is actually a substitute for the whole sentence. Those who regard مَا الْحَاقَّةُ to be its khabar (enunciative) have made an erroneous conclusion. The style adopted in these verses is adopted when it is meant to shake and jolt the addressee, especially an indifferent one. In such situations, a mention of the mubtadā’ (inchoative) is enough. The khabar is not mentioned so that all the attention of the addressee is focused on the mubtadā’. Similarly, the ambiguity which as a result is found in the sentence also attracts the attention of the addressee.
الْحَاقَّةُ (the Inevitable) is from among the names of the Day of Judgement. This name not only expresses the certainty of its happening but why it should necessarily happen vis a vis common sense and morality. The arguments of both these aspects can also be seen in the exegesis of the previous sūrahs. Some indications can also be seen in this sūrah, and the subsequent surāhs also contain some of its very significant aspects.
Though this word primarily refers to the Day of Judgement, also included in it in a secondary manner is the punishment which a nation necessarily faces if it rejects its messenger. The reason for this is that this punishment is also a prelude to the punishment on the Day of Judgement and also its substantiation and in fact comes because of the rejection of this Day. The messengers of God have simultaneously warned their respective nations of two punishments: the punishment of the Day of Judgement and the punishment which is a necessary outcome of denying this Day. When the people of these messengers denied the Day of Judgement and regarded a messenger’s standard of veracity to be the very punishment with which they were threatened if they denied this Day, then this punishment did come to them after the truth was conclusively communicated to them. Since every word and promise of God and every warning of the messenger is true, hence this punishment also is الْحَاقَّةُ ie something which is bound to happen.
مَا الْحَاقَّةُ is a powerful expression of the horror and dreadfulness which is further explained by the subsequent words: وَمَا أَدْرَاكَ مَا الْحَاقَّةُ. In other words, the implied meaning is that who can know and who can tell what this inevitable incident is and when it comes what will happen to those who today are obdurately denying it.
In Sūrah Qāri‘ah also, this style of address can be witnessed. I will inshallāh further explain it there.