'And fear a Day when no soul shall suffice for another soul at all, nor will intercession be accepted from it, nor will compensation be taken from it, nor will they be aided'
(Suarha al-Baqara 2:48)
This verse, as is clear, refers to Judgement Day. This event, of cosmic significance, is variously referred to in the Quran. The 'Opening of the Book' (Surah al-Fatihah) calls it Yaum al-Din ('The Day of Religion'), whilst other passages refer to it by a wider number of terms. Although these names add extra dimensions to our understanding, the central point is not so much intellectual as it is experiential (so to speak). That is, all of humanity must pass through God's awful judgement on that Day. Each deed (and misdeed) will be weighed in the balance and judged (O Allah, let me and mine not be found wanting)! Every individual soul will have to meet Allah in person and will have to explain the course of their life and their responses to it: the question will asked 'what did you do with the life and ability which I gave you?'
Belief in the existence of the Last Day is a fundamental part of Islamic Doctrine (`Aqida) and this is based on numerous Quranic passages and Prophetic Traditions (such as 2:177). As such, it forms part of the basic Islamic catechism and is known as such by every Muslim (from child to old man).
The idea of judgement is an important one and is meant to act in two main ways. That is, it is meant to inspire us to good works, in the hope of earning God's pleasure. It is also meant to keep us from sinning, through fear of God's wrath. Fear and hope, two quintessential features of Islam.
It's time for the maghrib prayer here in South Wales. So, I'll close here and God willing, I'll add a little more later. Insha Allah, I think I might add Ibn Kathir's tafsir (exegesis) to this verse.