"To judgment is our destination on the Day of Gathering, And in front of Allah will be gathered all adversaries."
Sufficient justice and retribution for the believer is that he waits for the day wherein Allah will gather the first and the last (of creation). The judge on that day will be Allah and the witnesses will be the angels:
(And we shall set up balances of justice on the Day of Resurrection, then none will be dealt with unjustly in anything. And if there be the weight of a mustard seed, we will bring it. And Sufficient are we as Reckoners)
(Quran 21: 47)