Belief in the Last Day implies belief in everything that the Quran or the Prophet (peace be upon him) has stated about the events of that Day and thereafter. There are some general aspects (resurrection, judgment and reward, Paradise and Hell) that every Muslim should be aware of and believe in with certainty. There are also more detailed aspects that the Quran or the Messenger of Allah (peace be upon him) mentioned. The more one has knowledge of that Day and its surrounding events, the greater the effect this belief will have on him. Hence, it is highly recommended for each individual Muslim to learn about the events that occur prior to and on the Day of Resurrection.
According to ibn Uthaimeen, belief in the last day encompasses three aspects. First is belief in the Resurrection: after the Second Blowing of the Horn, the people will be resurrected in front of Allah. They shall be naked, barefoot and uncircumcised.
The second aspect is belief in the accounting or reckoning of the deeds and the reward/punishment for those deeds. This aspect is mentioned and stressed in numerous places in the Quran.
The third essential aspect of belief in the Last Day is belief in Heaven and Hell. Heaven is the eternal abode or reward for the believers. Hell is the eternal abode of punishment for the disbelievers. The stronger opinion is that they both are in existence at this present time and they both shall exist forever. They are not simply states of mind as some non-Muslims and a few heretical Muslims believe. Allah and His Messenger made mention of them and have described them clearly and in unequivocal terms. There is absolutely no room for any Muslim to deny their existence or their descriptions.