Atheist Stephen Law challenges monotheists everywhere to explain "why the good god hypothesis should be considered significantly more reasonable than the evil god hypothesis". Most classical theistic arguments for the existence of God, Dr. Law claims, even if successful in proving an omnipotent and omniscient God, do nothing to speak to His moral character. Rather, this hypothetical God's positive moral character is simply asserted or assumed, or is supposed due to the existence of good in the world. By contrast however, many question how an omnipotent and omniscient God can possibly be good given that there is so much evil in the world. In his Evil God Challenge, Dr. Law goes on to explain that the most common excuses for why there is evil in the world in spite of the existence of an omnipotent, omniscient and good God can also be used to explain the opposite -- why there is good in the world in spite of the existence of an omnipotent, omniscient and evil God! Thus, the challenge...
The question as stated, however, is too vague to answer. After all, what is meant by the term "evil", and what is meant by the term "good"?
A Muslim would insist that acknowledging Mohammed as a prophet is "good", but worshiping Jesus as God is "evil". A Christian, on the other hand, would say exactly the opposite. Under Buddhism, self-denial is "good", but under hedonism, self is the only thing that really matters. Atheism, unlike all of the above, necessitates an ad hoc, arbitrary and individualized formulation of moral values, since there is no accepted moral authority in an atheistic universe.
How we define these terms will (at least in part) determine how we respond to Dr. Law's challenge.
If, for example, "evil" is defined as "not doing what God commands" and "good" is defined as "doing what God commands", then it is almost beyond all imagining to suggest that an omnipotent and omniscient God commands Himself to do things, and then refuses to do them. With these definitions of good and evil, it is beyond question "significantly more reasonable" to suppose that God is good rather than that He is evil.
I asked Dr. Law for clarification on the definitions of these terms. After insisting the definitions of good and evil were not relevant to the challenge, he finally chose, unsurprisingly, to explain both "good" and "evil" in a decidedly humanist manner, revolving their meanings around the preferences of "sentient beings", specifically humans. In particular, from Dr. Law's perspective, that which seems in general to cause humans immense pain or suffering was deemed "evil".
But by a humanist definition of evil, of course the God of the Bible is evil. No coherent argument can possibly be proffered to deny this. (Genesis 7:4, 11:6-8, 19:24-25; Exodus 12:12; Deuteronomy 32:39; 1 Samuel 15:3; Job 1:21; Hosea 13:16; Matthew 22:13, 24:51; Luke 20:16; 2 Thessalonians 2:11; Revelation 6:4, 6:8)
But so what?
All that has been agreed to by saying that God disobeys humanist values is to say that God is not a humanist -- He does not hold humans in the place of God, as humanists do. Since humanism, the inappropriate exaltation of humans to the position of universally supreme importance, is in fact inappropriate, we would not expect an omniscient God to fall prey to such silliness. In other words, if there is an omniscient God, of course He is not a humanist. He would know that because He Himself exists, humans are not of supreme importance -- He is. This means that humanist values would not be His values. This means that He would of necessity be, according to humanism, opposed to "good" and in favor of "evil".
The existence of any kind of omnipotent, omniscient God is antithetical to humanism. If there is a God, then humanism is false and humanistic values are inappropriate, unjustified, and illogical. Therefore, the existence of any kind of omnipotent, omniscient God necessitates that He be evil from a humanist perspective. The contrary is simply incoherent.
But this is not problematic for Christians in the least -- Christians are not humanists.
Christianity views moral evil as disobedience to the God revealed in the Bible, and moral good as obedience to that same God (Malachi 3:18; Romans 4:15, 5:13; 1 John 3:4). God is always morally good because He never gives Himself commands that He disobeys. Using a Christian understanding of moral good and moral evil, it is "significantly more reasonable" to conclude that the omnipotent and omniscient God who exists is good, obeying Himself, than it is to conclude that He is evil, disobeying Himself.
Humans are not, and never have been, ultimately sovereign. This is true for humanity in general, and it is also true for each human individually.
Since you yourself, for example, did not create humanity, humanity is not obligated in any moral way to please you. Your whims are not in control of the rest of us. You began to exist, just like every other human being. You are not the center of the universe. What pains you is not automatically something that everyone around you should avoid. You are not in control of reality. Your desires are, quite simply, not particularly important.
But there is a God who created you -- you and everything else that has begun to exist (Genesis 1:1; John 1:3; Colossians 1:16). This God has commanded you, along with all humans, to worship Him (Acts 17:30; Matthew 22:37-38; Luke 4:8). If you do not worship the God who created you, you are disobeying His command.
This makes you evil.
But there is hope. The God who created you not only demands your obedience, but He has also provided forgiveness for your disobedience. He has done this through His Son, the person known as Jesus the Christ. He has offered you His love and forgiveness on the condition that you accept the sacrifice and Lordship of His Son. (Matthew 10:32; John 14:6; Romans 6:23, 10:9-10; Acts 16:31; 1 Corinthians 1:21; Galatians 3:22)
There is no better time than now to turn from evil to the only one who is perfectly good -- the God who created you and graciously caused His own Son to suffer your punishment in your place for your evil rebellion (Isaiah 53:10; John 3:16-17; Acts 4:27-28; Romans 3:23, 6:6; Galatians 2:20).