Nasai

(1) "On the Day of Resurrection": The apparent wording of the narration indicates that this gathering will not occur on the Day of Resurrection itself, but rather before it. Many hadith scholars have mentioned such narrations among the signs of the Hour, because they mention camels, midday, night, morning, and evening. Clearly, these things exist in this world, not on the Day of Resurrection. Although some scholars have interpreted it as referring to the actual Day of Resurrection, this interpretation is quite forced. "The Day of Resurrection" may also refer to the time close to the Hour, and this is the correct view.

(2) "In three states": That is, some will be purely righteous, some will have mixed deeds, and some will be outright disbelievers. Or, it may mean three states of gathering: some people, under the influence of eagerness and fear, will reach the place of gathering on their own at the appointed time; some, during a time of hardship when mounts are scarce, will flee and arrive with great difficulty, riding two, three, four, or even more on a single camel; and some will be forcibly gathered together with the fire.

(3) This fire will emerge from the coast of Aden before the Resurrection. (Sahih Muslim, Chapter on the Signs that will Occur before the Hour, Hadith: 2901) Some people have interpreted this fire as a trial (fitnah) rather than actual fire, and metaphorically, a trial is sometimes called a fire. However, the first view is correct. And Allah knows best.

Hadith Commentary:
Islamic scholars have interpreted this fire to refer to several fiery incidents. However, the true reality is known only to Allah. Our faith is that the Messenger of Allah sallallahu alayhi wa sallam spoke the truth.

Hadith Commentary:
The people who will be gathered in the Plain of Resurrection will consist of three categories, as detailed in the hadith, and this gathering (hashr) will take place at the end of the world, before the Day of Judgment, because in the upcoming hadith it is clarified that you will meet Allah, barefoot, naked, walking on foot, and spontaneously. It is also clarified that the disbeliever will walk on his face on that day.
From this clarification, it is understood that the gathering (hashr) mentioned in the hadith will occur shortly before the Day of Judgment.
And Allah knows best.

Hadith Commentary: Benefits and Issues: The meaning derived from this hadith is that, near the Day of Judgment, people will head towards a safe place out of fear of the fire. This fire will emerge from the depths of ‘Adn. In order to escape it, people will flee towards secure locations. The prosperous and well-off individuals, with good provisions and mounts, will set out, desiring safety and fearing to remain in their own places.

➊ The second group, due to the scarcity of mounts, will travel two by two, three by three, until even ten companions will take turns riding on a single camel.

➋ The third group will not find any mounts at all; they will flee on foot.

➌ The fire will not cease to pursue them; it will remain with them at all times and in every place.