The belief in life after death not only guarantees success in the Hereafter but also makes this world full of peace and happiness by making individuals most responsible and dutiful in their activities.
Think of the people of Arabia before the arrival of the Prophet Muhammad . Gambling, wine, tribal feuds, plundering and murdering were their main traits when they had no belief in life after death. But as soon as they accepted the belief in the One God and life after death they became the most disciplined nation of the world. They gave up their vices, helped each other in hours of need, and settled all their disputes on the basis of justice and equality. Similarly the denial of life after death has its consequences not only in the Hereafter but also in this world. When a nation as a whole denies it, all kinds of evils and corruption become rampant in that society and ultimately it is destroyed.
The Quran mentions the terrible end of Aad, Thamud and the Pharaoh in some detail:
[The tribes of] Thamud and Aad denied the Striking Calamity [i.e. the Resurrection]. So as for Thamud, they were destroyed by the overpowering [blast]. And as for Aad, they were destroyed by a screaming, violent wind which He [i.e. God] imposed upon them for seven nights and eight days in succession, so you would see the people therein fallen as if they were hollow trunks of palm trees. Then do you see of them any remains? And there came Pharaoh and those before him and the overturned cities (i.e. those to which Lot was sent) with sin. And they disobeyed the messenger of their Lord, so He seized them with a seizure exceeding [in severity]. Indeed, when the water overflowed, We carried you [i.e. your ancestors] in the sailing ship (i.e. which was constructed by Noah). That We might make it for you a reminder and [that] a conscious ear would be conscious of it. (Quran, 69:4-12)
Think of the people of Arabia before the arrival of the Prophet Muhammad . Gambling, wine, tribal feuds, plundering and murdering were their main traits when they had no belief in life after death. But as soon as they accepted the belief in the One God and life after death they became the most disciplined nation of the world. They gave up their vices, helped each other in hours of need, and settled all their disputes on the basis of justice and equality. Similarly the denial of life after death has its consequences not only in the Hereafter but also in this world. When a nation as a whole denies it, all kinds of evils and corruption become rampant in that society and ultimately it is destroyed.
The Quran mentions the terrible end of Aad, Thamud and the Pharaoh in some detail:
[The tribes of] Thamud and Aad denied the Striking Calamity [i.e. the Resurrection]. So as for Thamud, they were destroyed by the overpowering [blast]. And as for Aad, they were destroyed by a screaming, violent wind which He [i.e. God] imposed upon them for seven nights and eight days in succession, so you would see the people therein fallen as if they were hollow trunks of palm trees. Then do you see of them any remains? And there came Pharaoh and those before him and the overturned cities (i.e. those to which Lot was sent) with sin. And they disobeyed the messenger of their Lord, so He seized them with a seizure exceeding [in severity]. Indeed, when the water overflowed, We carried you [i.e. your ancestors] in the sailing ship (i.e. which was constructed by Noah). That We might make it for you a reminder and [that] a conscious ear would be conscious of it. (Quran, 69:4-12)