The Day of Judgement
This world is a temporary life. After death, we will all be resurrected, on the Day of Judgement, and called to account for our deeds, and recompensed accordingly. Those who may have escaped justice in this world, will not be able to escape and will face absolute justice.
Those who believed in and worshipped God alone, obeyed Him, and did good deeds with sincerity, will, through God’s mercy, after being judged by Him, be admitted into Paradise. God will also judge those who rejected His message, disobeyed Him, did evil deeds etc; those deemed deserving will go into hell. Nobody will be wronged in the slightest, not even by a dot. It will be the day of perfect justice, for God is the most Just.
The door to repentance is open in this world. For all who repent, pray for forgiveness, and resolve sincerely to try not to repeat past mistakes, God is Forgiving, Merciful.