Most religious systems out there have some idea of “justice”: those who are good get rewarded, and those who are evil get punished.
Christianity postpones it to the afterlife: good people go to Heaven and evil people go to Hell. Some Eastern religions say it'll happen either later in this life or in a future one: good people get rewarded with good karma, and evil people get punished with bad karma.
It's just part of the religious framework, I think.
We, as humans, seem to have an egoic need to see good people rewarded and bad people punished. We celebrate when a murderer gets the death penalty. We root for the hero in a movie to have his happy ending.
But is there really justice in the Universe? Does the Universe care about right and wrong? Does the law of attraction bring good things to good people, and bad things to bad people?