An omnipotent being [if he exists], who created a world containing evil [or potential for evil] not due to [its] sin must himself be at least partially evil [i.e. sinful].
— Bertrand Russell
(Bertrand Russell’s Best)
The Greek philosopher Epicurus (c. 341–270 BCE) is usually said to be the first to highlight the classic ‘problem of evil’. With the undeniable presence of much suffering that continues to arise from evil in this world, he said, ‘ Is God, [if he exists], willing to prevent evil, but not able? Then he is not omnipotent [i.e. all-powerful].  Is he able, but not willing? Then he is malevolent [i.e. not all-loving; omnibenevolent].  Is he both able and willing? Then whence cometh evil? [i.e. Then from where comes evil?]  Is he neither able nor willing? Then why call him God, [if he ‘does’ exist]?’
The above is sometimes called the ‘Epicurean paradox, riddle or trilemma (of the impossible coexisting of omnipotence, omnibenevolence with evil),’. However, there is no true unresolvable paradox, unanswerable riddle or stalemated dilemma, because there is a simple and direct conclusion — that there is no all-governing deity, a ‘God’ with a capital letter ‘G’, as assumed to exist, who is omnipotent and omnibenevolent, as he or she cannot exist. The problem of evil is problematic only if there are force-fitting attempts to impossibly reconcile the presence of much evil with the presence of one who should be able and willing to banish it all right now.
Rewording Epicurus’ thought as statements instead of questions for greater clarity, it could be so — ‘ If there is a deity not able to prevent evil, although willing, (even to the extent of being omnibenevolent), he is not omnipotent, (since there is still clearly much evil in the world).  If there is a deity able to prevent evil, (even to the extent of being omnipotent), although not willing, he is not omnibenevolent, (since there is still clearly much evil in the world).  If there is a deity able and willing to prevent evil, (even to the extent of being omnipotent and omnibenevolent), there should be no evil. (Yet, since there is still clearly much evil in the world, such a deity does not exist.)  If there is a deity not able and not willing to prevent evil, (even to the extent of not being omnipotent and omnibenevolent), there is no reason to call him a deity (who is omnipotent and omnibenevolent).’
Epicurus thought was in terms of two ‘omni’ qualities. Sometimes, there are two more ‘omnis’ added as essential qualities of a supposedly ‘almighty creator, sustainer and destroyer of all’ — omnipresence (which is to be all-present), and omniscience (which is to be all-knowing). We can say that omnipotence and omnibenevolence should by default contain omnipresence and omniscience too, since being all-powerful and all-kind should lead to being everywhere (to govern all and care for all), with knowledge of everything (as knowledge is power and needed to care well).
Although the above reasoning implies there is no almighty creator deity with all two (or four) ‘omnis’, it does not prove that there are no less mighty deities with some limited potence and benevolence. However, being imperfect, they would not be subjects for perfect spiritual refuge, as they might not be powerful or benevolent enough in times of need. Such is taught in Buddhism, which does respectfully acknowledge the existence of various deities, including those who have mistaken themselves to be creators of the world and humankind, who have more positive karma than humans for the time being, though yet to be liberated from the rounds of rebirth.
There are three classic theodicies, which are proposed methods of vindicating the God idea despite the problem of evil, followed by their shortfalls.  First, is the proposal that for the best possible world to be possible, there must be free will, which means some will choose to be evil.  Second, is the proposal that evil must exist by default, as the polar opposite of good, for there to be good.  Third, is the proposal that there is no perfect creation in the first place, with its imperfections needed to toughen us up in character.
Applying universally to these theodicies is this irrefutable rebuttal… If there is an omnipotent creator of the world, why should there be such severely yet arbitrarily self-limiting nature, that ‘necessitates’ creation that inevitably leads to so much evil and suffering? Why would a perfect creator not create the absolutely pure and perfect in the first place (which is beyond good and evil), to disable  the potential of choosing evil,  the ‘need’ to have evil, and  the struggle to work towards good? If even we imperfect beings would not create dangerous environments at home and in the community with  evil potentials deemed  ‘needed’ for  struggle, why would a perfect being do so? An omniscient creator should had expected the proliferation of evil, and with omnibenevolence prevented it in the first place. These theodicies also do not answer why those who are apparently not evil in this life suffer from external ‘evils’, in terms of wars, pandemics, natural disasters and such. Not only not adequately answering the basic problem of evil, these theodicies thus create more complex problems.
Truth be said, based on the omnipotence ‘paradox’, focusing on ‘omnipotence’ alone, it is already enough to know that belief in it is confused. As Will Bynoe wrote on the omnipotence ‘paradox’, ‘[I]f He [i.e. God] is all-powerful, can He create a stone so heavy He can’t lift it?… If He can, He can’t lift the stone. So He’s not all-powerful. And if He can’t, there’s something He can’t do. So he’s not all-powerful. So the concept of God is confused’ [as He is not all-powerful either way].
As a somewhat similar teaching retold by the Buddha of what he once taught as a Bodhisattva in a previous life, which surely predated Epicurus’ teaching (!), are these verses in the Bhūridatta-Jātaka (453), as translated by E. B. Cowell and W. H. D. Rouse, with notes in between, that relate to the four ‘omnis’, ‘.  He who has eyes can see the sickening sight [of evil and suffering in the world]; why does not Bráhma [here equivalent to the assumed ‘creator’ deity] set his creatures right [by removing and preventing evil and suffering]?  If his wide power no limit can restrain, [if he is omnipresent and omnipotent], why is his hand so rarely spread to bless?  Why are all his creatures condemned to pain [of birth, sickness, ageing, death and more]? Why does he not to all give happiness [if he is omnibenevolent]?  Why do fraud, lies, and ignorance prevail? Why triumphs falsehood — truth and justice fail [if he is omniscient]?  I count your Bráhma one the unjust among, who made a world in which to shelter wrong [if he did make it].’
Buddhists take ultimate refuge in the Buddhas instead, who are ‘Teachers Of Humans And Gods’ (人天教主), as they are fully enlightened and liberated. As stated in the ‘Verses On The Greatest Power’ (大力偈), ‘ Since having immeasurable suffering, the world is without this [creator] deity [imagined to have omnipotence, omnibenevolence and omniscience]. Only having immeasurable Buddhas, complete with omnibenevolence and omniscience.  Omnibenevolent with the greatest loving-kindness and compassion, omniscient with the greatest wisdom, and all complete with the greatest supernormal powers, complete with the greatest abilities possible [i.e. with “maxi(mum)-potence”].  There is Āmítuófó (i.e. Amitā[bha] Buddha), who expresses all Buddhas’ great powers, who created the Pure Land Of Ultimate Bliss, encouraging all to, with Faith and Aspiration, be mindful of the Buddha’s name.  With Self-power connecting to Other-power, attaining the Buddha’s great empowerment, in the present life and the future life, depart from suffering and attain bliss. ( 既有无量苦，世间无此神。唯有无量佛，具全爱与知。 全爱大慈悲，全知大智慧，全具大神通，具最大能力。 有阿弥陀佛，表诸佛大力，创立极乐国，劝信愿念佛。 自力感他力，得佛大加持，今生与来世，离苦而得乐。)
 The Buddhas are not deities who created this world; only creating Pure Lands [which are free from all evil and suffering]. This defiled land is with our collective karma connected [and created], and my suffering is all self-attracted.  The Buddhas, although are without omnipotence, not able to, without cause and conditions, remove all the world’s suffering instantly, their great powers await us to be called upon.  The Buddhas for expressing omnibenevolence, created Pure Lands and encourage birth in them. The Buddhas for expressing omniscience, already perfected their Buddha Lands.  Encouraging you to quickly take [the “highest”] refuge, in Āmítuófó, our spiritual “Father” with great loving-kindness. His Pure Land Of Ultimate Bliss [which is the easiest to reach, through which all other Pure Lands can be reached], is precisely for you and me.’ ( 佛非创世神，唯创净国土。秽土共业感，吾苦皆自召。 佛虽无全能，不能无缘拔，世间一切苦，大力待感召。 佛为表全爱，创净土劝生。佛为表全知，已圆满佛国。 劝君速皈依，弥陀大慈父。极乐世界国，即为您和我。) For the problem of evil and the suffering it causes, for both now and hereafter, the Pure Land teachings offer the most streamlined solutions to transform evil and suffering, to become purity and bliss, at both individual and communal levels. Námó Āmítuófó.
We are told that sin consists in acting contrary to God’s commands, [if he exists], but we are also told that God is [supposedly] omnipotent. If he is, nothing contrary to his will can occur; therefore when the sinner disobeys his commands, he must have intended this to happen [by freely allowing it to happen, despite supposedly knowing the consequences, which would make him not omnibenevolent].
— Bertrand Russell
(The Basic Writings Of Bertrand Russell)
How Do Pure Land And Deity-Centric Teachings Differ?
How Is Āmítuófó Our Loving ‘Father’?
Can Faith In Any Deity Help The Dying?
The Buddha’s Victory Over A God And Demon
How Does Buddhism Explain Creation?
How Can A ‘Creator’ Be ‘Created’?
How Were The ‘First’ Humans ‘Created’?
Complete ‘Verses On The Greatest Power’
Are Buddhas Omnipotent, Omnibenevolent And Omniscient?