One of the underlying facts of the Abrahamic faiths is the concept, that God is simultaneously both omnipotent and Omni-benevolent. They all also argue that God is the single and only cause of the existence of the Universe, and all of its constituents. One of the constituents is the existence of evil. The problem that theists face is, an argument that both atheists and anti-theists use to criticise religion, and question against God; How come Omni-potent God and Omni-Benevolent God, can exist alongside the existence of both Natural and Moral Evil, or at least tolerate it’s occurrence. This comes in the form of the ‘inconsistent triad’ in which , if one were take out either one of the 2 tributes of God, could solve the existence of Evil. To elaborate, if God was omnipotent, though not Omni-benevolent, it would explain, that this God is either Tyrannical, or in a way at the least Sadistic, resembling the God of the Old Testament. On the other hand, if God is Omni-benevolent, he would love humanity, yet does not have the power, to directly prevent it from happening to humanity. Many scholars and theologians, have attempted at solving the problem of evil using theodicies (Justifying the existence of God in the face of evil), two of which were concocted by Irenaean and Leibniz, but include theodicies by St. Augustine and Alfred Whiteheads’ Process theodicy.
Irenaeus’ theodicy, argued (like St. Augustine) that moral evil, is the doing of man, by being deviant in their belief in God and faith. However, he argued that God is at least partly to blame for the evil and suffering in this world, by creating the world imperfectly deliberately. Iranaeus; reasoning was that so an individual can get closer to God through faith, in a ‘Soul making ‘process, to become a sort of ‘Child of God’, if you will. Stating, that only through suffering could one become virtuous in nature. As suffering is needed to appreciate life in its entirety. He also stated, that God could not have created us in his image, as that could have only done by attaining the likeness of God, which needed cooperation, therefore, God created us with free will to have our ‘willing’ co-operation. The Irenaean theodicy, was further developed and refined by John Hick, who highlighted the importance of God allowing, human beings to developing ones personality, hence ‘Soul making’. He reasoned that if God had made us perfect, we would have been akin to robots, and God wanted us to believe that we are genuinely loving – to do this he needed to give us free will.
Another attempt at justifying the existence of God in the face of evil, is Leibniz’s ‘The Best of all worlds’ theodicy. For Leibniz, an additional central concern is the matter of reconciling human freedom, with the determinism inherent in his own theory of the universe. Leibniz' solution casts God as a kind of "optimiser" of the collection of all original possibilities: Since he is inherently Omni-benevolent and omnipotent, and since he chose this world out of all possibilities, this world must be good—in fact, this world is the best of all possible worlds.

On the one hand, this view might help us rationalize some of what we experience: Imagine that all the world is made of good and evil. The best possible world would have the most good and the least evil. Courage is better than no courage. It might be observed, then, that without evil to challenge us, there can be no courage. Since evil brings out the best aspects of humanity, evil is regarded as necessary. So in creating this world God made some evil to make the best of all possible worlds. On the other hand, the theory explains evil not by denying it or even rationalizing it—but simply by declaring it to be part of the optimum combination of elements that comprise the best possible godly choice. Leibniz thus does not claim that the world is overall very good, but that because of the necessary interconnections of goods and evils, God, though omnipotent, could not improve it in one way without making it worse in some other way.

Whether or not these theodicies are successful, is a matter of how, one would perceive religion, or the faith it extends from. One could easily argue that the arguments have had a hand in easing the blow, of the existence of evil on theists. However, they have been unsuccessful in such to solve the problem of evil in its entirety. As, though they have given a reason, for the existence of evil, their arguments still have many potholes. For example, in the Irenaean theodicy, suffering is seen as a necessary thing to endure, to become closer to God, yet the magnitude of suffering, does not seem to equate with the end reward, the holocaust and 9/11 are both atrocities that can both be viewed as an evil to endure. However, the deaths of 6 million innocent lives, does not seem to justify the ‘Soul making’ process. D.Z. Phillips wrote in his book ‘The concept of prayer’, argued that the existence of evil, is not a demonstration of love, from an Omni-benevolent God, though this has been countered, that the magnitude of suffering, could be justified by a supposed supremely good future in heaven.
For Leibniz’s case, Voltaire and Bertrand Russell both argued against the theodicy. Voltaire, argued that the world contains an amount of suffering too great and sever to justify any optimism belief that God has created the "best of all possible worlds". The optimism itself, could also be questioned except. Leibniz argued that the nature of God, is inherently that of good nature, yet if this world is the ‘best possible world’, then the nature of said deity is inherently sadistic. While Leibniz argued that suffering is good because it incites human will, critics argue that Leibniz also addresses this concern by considering what God desires to occur (his antecedent will) and what God allows to occur (his consequent will). Others, such as the Christian philosopher Alvin Plantinga criticized Leibniz's theodicy by arguing that there probably is not such a thing as the best of all possible worlds, since one can always conceive a better world, such as a world with one more morally righteous person. As in the case of omnipotence, it would contradict the idea, that God could not improve Earth in one way without making it worse in some other way, as being all powerful, would be sufficient to create a rapture, if he truly intended to be that of a best world, he would have created a world that resembled heaven, as in any case, that would be the best basis for a world.
To my mind, neither of these theodicies (if any), is sufficient to argue, the justification of God. In my own personal view, only Islam, can answer the problem of evil. Judaism and Christianity both argue that God, is both Omni-benevolent and omnipotent, and as the inconsistent triad proved, this cannot occur. Islam, teaches that Allah, is not Omni-benevolent (as humanity must earn his love, due to the fact that we need him not him needing us) but Omni-donantes (all forgiving), for when we commit a sin we can supplicate to God, to forgive us of our sins. This solves the concept of moral evil, however, the concept of natural evil, is more of a warning to humanity, for us not to deviate from our faith.