Belief in Last Day

It is to believe that the life of this world will come to an end. Allah (y) says: Whatsoever is on the earth will perish. [55:26]

To believe in the life of the Barzakh: This life is the time after one’s death until the Last Day. In it, the believer will live a life of pleasure, while the disbeliever will be punished. Allah (y) says: The Fire; they are exposed to it, morning and afternoon, And the Day the Hour appears [it will be said], "Make the people of Pharaoh enter the severest punishment." [40:46]
To believe in the Resurrection: Allah will resurrect mankind, naked, barefooted, and uncircumcised. Allah (y) says: The disbelievers claim that they will never be resurrected. Say, "Yes, by my Lord, you will surely be resurrected; then you will surely be informed of what you did. And that, for Allah, is easy." [64:7]
To believe in the Gathering: Allah will gather all creation together and call them to account. Allah (y) says: And [warn of] the Day when We will remove the mountains and you will see the earth prominent, and We will gather them and not leave behind from them anyone. [18:47]
To believe that people will be brought before Allah in rows: Allah (y) says: And they shall be brought before your Lord, standing in rows: "You have certainly come to Us just as We created you the first time. But you claimed that We would never make for you an appointment." [18:48]
To believe that one’s limbs will bear witness. Allah (y) says: Till, when they reach it, their hearing and their eyes, and their skins will testify against them as to what they used to do. And they will say to their skins, ‘Why do you testify against us?’ They will say: ‘Allah has caused us to speak, He causes all things to speak: and He created you the first time, and to Him you are made to return.’ And you have not been hiding yourselves, lest your ears, and your eyes, and your skins testify against you; but you thought that Allah knew not much of what you were doing. [41:20-22]
To believe in the Questioning. Allah (y) says: But stop them; verily they are to be questioned. [They will be asked], "What is [wrong] with you? Why do you not help each other?" But they, that Day, are in surrender. [37:24-26]
To believe in the Siraat (Bridge over the Hellfire) and that everyone must pass over it. Allah (y) says: There is not one of you but will pass over [Hell]; this is upon your Lord an inevitability decreed. [19:71]
To believe in the weighing of deeds. Allah will call people to account and reward those who did well with what they deserve, due to their righteous deeds, their faith, and adherence to their Messengers, and He will punish those who did evil. Allah (y) says: And We place the scales of justice for the Day of Resurrection, so no soul will be treated unjustly at all. And if there is [even] the weight of a mustard seed, We will bring it forth. And sufficient are We as accountant. [21:47]
To believe in the handing out of Scrolls and Books. Allah (y) says: Then, as for him who will be given his Record in his right hand, He surely will receive an easy reckoning. And he will return to his family in joy! But whosoever is given his Record behind his back. He will cry out for destruction. And [enter to] burn in a Blaze. [84:7-12]
To believe that people will be rewarded with Jannah or Hellfire in an everlasting and eternal life that will never end. Allah (y) says: Verily, they who disbelieved among the People of the Scripture and the polytheists will be in the fire of Hell, abiding eternally therein. Those are the worst of creatures. Verily, those who believe and do righteous deeds, they are the best of creatures. Their reward with Allah will be gardens of perpetual residence beneath which rivers flow, wherein they will abide forever, Allah being pleased with them and they with Him. That is for whoever has feared his Lord. [98:6-8]
To believe in the Hawd,Intercession, and all other things which the Messenger of Allah (y) informed us.

The Merits of Belief in the Last Day:

It would make one prepare himself for that Day, by performing good deeds, and competing therein, and abstaining from sinful acts and fearing His punishment.
It would comfort the believers; since they know what they missed in this world, Allah would reward them with better in the Hereafter.
To distinguish the believers who are truthful in their faith from those who are not.