وَٱلَّذِينَ يُؤْمِنُونَ بِمَآ أُنزِلَ إِلَيْكَ وَمَآ أُنزِلَ مِن قَبْلِكَ وَبِٱلْـَٔاخِرَةِ هُمْ يُوقِنُونَ
Wa'lladhīna yuʾminūna bimā unzila ilayka wa mā unzila min qablika wa bi'l-ākhirati hum yūqinūn "And those who believe in what has been sent down to you and in what was sent down before you; and of the hereafter they are certain."
This verse is one of the fundamental texts showing how Islam positions itself. What counts as a condition of faith is not only "what has been sent down to you" but "what was sent down before you".
The text presents itself, then, not as a new religion but as the last link of a chain that had been interrupted. This is also why the history of the Children of Israel is recounted at such length in the sections ahead: what is recounted is not the story of a foreign nation but the earlier links of the same chain.
The verb أُنزِلَ comes in the passive: "it was sent down", the sender is not named. Using the passive where the agent is obvious is common in Arabic, and here it also quietly stresses that the text is not a human work — the book was not written, it was sent down.
Root ʾ-kh-r: what comes after, what is left behind. Al-ākhira = the last, the other one. The word's pair is al-dunyā, and that comes from the root d-n-w: what is near, what is lower.
The names the Qurʾān uses for the two lives, then, state not a judgement of value but a position: the near one and the one that comes after. This world is not named "dunyā" because it is bad, but because it is near. And in fact the human being's basic problem is described right here — it is easy to see what is near, and hard to take into account what comes after.
This is the striking side of the verse. At the head of the sentence the verb yuʾminūn (they believe) is used twice; when it comes to the hereafter the verb changes: yūqinūn.
Yaqīn is a word from the root y-q-n, and it means certain knowledge from which doubt has been entirely removed. It carries an association like sediment settling to the bottom, like turbidity clearing. It is a degree beyond faith: faith is to trust, whereas yaqīn is the closing of the argument.
Why for the hereafter in particular? Because throughout history this is the article of belief most objected to and most mocked. The objections the Qurʾān reports all gather at the same place: "When we have become dust, shall we really be created anew?" (al-Raʿd 13/5). The idea of God is found negotiable; the idea of rising after death is refused outright.
هُمْ يُوقِنُونَ — there is also a pronoun in the sentence that looks superfluous: "they, they are certain". In Arabic this pronoun repeated after the subject conveys takhṣīṣ (specification). The meaning shifts to this: it is they who are certain of the hereafter. The emphasis implies that others are slack on this point.