The reason why there will be so many people in Hell is not that the truth failed to reach them all, wherever or whenever they lived. Allah does not blame anyone whom His call did not reach:
“..Nor would We punish with Our Wrath until We had sent a Messenger [to give warning].” (17:15)
“..And there never was a people, without a Warner having lived among them [in the past]”. (35:24)
The reason behind it is the fact that those who responded to the Messengers were few in number, while those who disbelieved were great. Furthermore, many of those who responded were not pure and sincere in faith.
In his book, at-Takhweef min an-Naar, Ibn Rajab discussed the reason why so few people will enter Paradise and so many will enter Hell: “These hadith and other similar reports prove that most of the children of Aadam will enter Hell and that the followers of the Messengers are few in number when compared to the rest of mankind. Those who did not follow the Messengers will enter Hell, except for those whom the Message did not reach, or who could not understand it because of the garbled form in which they heard it. Many of those who claim to be followers of the Messengers are in fact adhering to a distorted religion and an altered book, and they too will be among the people of Hell, ” as Allah (SWT) says: “…But those of the sects that reject it [the Qur’an] the Fire will be their promised meeting-place” (11:17)
As for those who claim to follow the Book and Law of Allah (SWT) the true religion, many of them will also enter Hell. These are the Munaafiqoon (the hypocrites) who will be in the lowest level of the Fire. Many of those who claim to follow it openly and in secret will be tested by ambiguities and doubts – these are the misguided inventors and followers of bid’ah (reprehensible innovations, heresies). Several hadith have been narrated which state that the ummah will split into seventy-odd sects, all of which will be in Hell except for one. Many people will also be tested with forbidden desires for which the promised punishment is Hellfire, although in this case, it is not necessarily an eternal punishment. No one from this ummah will be saved from the Fire, or deserve the absolute promise of Paradise, apart from the one sect or group, who follow the example and practice of the Prophet (saw) and his Companions openly and in secret, and are saved from the temptation and trials of desires and doubts. Such are very few indeed, especially in latter times”. (at-Takhweef min an-Naar, Ibn Rajab, p.214)
The main reason why so many follow their desires is that the love of such things is deeply rooted in the human psyche: “Fair in the eyes of men is the love of things they covet: women and children; heaved-up hoards of gold and silver [wealth]; horses branded [for blood and excellence]; and [wealth of] cattle and well-tilled land. Such are the possessions of this world’s life..” (3:14)
Many people want to fulfill these desires in whatever way they wish, without paying attention to the revealed laws of Allah (SWT), and by adhering to the customs of their forefathers in ways that contradict these laws
“Just in the same way, whenever We sent a Warner before you [Muhammad] to any people, the wealthy ones among them said: “We found our fathers following a certain religion, and we will certainly follow in their footsteps”. [The Warner] said: “What! Even if I brought you better guidance than that which you found your fathers following?” They said, “For us, we deny that you [Prophets] are sent [on a mission at all]”. (43:23-24)
Loving the ways of one’s forefathers to the point of sanctifying them is a disease that many nations are suffering from, and its effects on the deeply-rooted desires of men are no less if it is not counted as a desire in itself.
at-Tirmidhi, Abu Dawud, and an-Nasaa’ee report from Abu Hurayrah (RA) that the Messenger of Allah (saw) said, “When Allah (SWT) created Hell, He told Jibreel, “Go and look at it.” Jibreel went and looked at it, and when he came back he said, “By Your Glory, I fear that no one who hears of it will enter it”. So He surrounded it with desires, and said, “Go and look at it.” Jibreel went and looked at it, and when he came back, he said, “By Your Glory, I fear that there will be no-one left who does not enter it”. (the version narrated by an-Nasaa’ee adds the words, “and at what I have prepared for its inhabitants in it”.) [Jaami al-Usool, 10/250, # 8068. at-Tirmidhi described it as sahih hasan].
al-Bukhaari and Muslim narrated from Abu Hurayrah that the Prophet (saw) said, “Hell is veiled in desires and Paradise is veiled in hardships”.
Siddeeq Hasan Khan said, “What is meant by desires is the things that people want and enjoy”. al-Qurtubee said, “Desires are all those things that people like and towards which they are inclined, and surrounding a thing means placing something all around it so that it cannot be reached without going through it”. (Yaqadhat uli al-I’tibar, p.220)