God says in the Quran:
“Verily, those who disbelieve and die in unbelief – an earth full of gold will never be accepted from them, even if they wanted to buy themselves off with it. These have a painful punishment and they will have no helpers. ” (Quran 3:91)
So this life is our only way to win paradise and escape from hellfire, because if someone dies in unbelief, they will not have the opportunity to go back to this world to believe. God says in the Quran how unbelievers will fare on the day of judgment:
“And if only you could see them put in front of the fire! Then they will say: ‚Oh, we would be brought back! We would not then declare our Lord’s signs to be lies and we would be among the believers! ‚”(Quran 6:27)
But no one will get this second opportunity.
The Prophet Muhammad said: “The happiest man in the world, whose fate will be fire on Judgment Day, will be immersed in the fire once. Then he will be asked: ‚Son of Adam, have you ever seen anything good? Did you ever get blessings? ‚ There he will say: ‚No, by God, oh Lord!‘ ”
 Narrated by Sahih Muslim, # 2807, and Musnad Ahmad, # 12699.