One of the arguments against non-belief in a god or gods or religion is that people would get away with injustices if there was no afterlife. Punishment in the form of hell (Christianity, Islam) or rebirth to a lower caste of life-form (Hinduism) solves that. God is merciful and yet administers firm justice.
Atheists on the other hand say that one can expect that people will sometimes get away with crimes against other people and prosper till they die with little price (but for one's conscience) to pay. It is an inevitable part of the human condition. That is an honest stand compared to the hypocritical stance of the major religions. Islam for example teaches that Allah will forgive anything except 'shirk' (belief in another God) or 'riddah' (apostasy, a Muslim denying Islam). In Christianity, you may do anything, yes any crime, no exceptions, and with asking forgiveness you will enjoy heaven. Aside from the fact that no one has any good evidence of heaven or hell, it also means that the concept of god's justice tempered with mercy is a fallacy. In Christianity you are told of hell, a punishment from the father, but you are offered a loophole of redemption due to the sacrifice, meaning cruel and unnecessary death of the son. In human terms, a judge can convict you and with mitigating circumstances can give you a lesser term than you deserve. Justice tempered with mercy. With condemnation to hell, how is there mercy? In the religious context, afterlife believers should admit that for them, justice and mercy are mutually exclusive terms. Roland Francis Toronto.