There is a myth that prior to Christopher Columbus, everyone thought the world was flat. This myth was invented by Washington Irving, a man who, by his own admission, was "apt to indulge in the imagination".
In reality, while some Christians did believe the flat Earth, they were few and far between. Many Christians, both orthodox and heretical, believed the Earth was round, and some traditions even persist based on their beliefs. But imagine, for a moment, the flat Earth myth really did persist until the time of Christopher Columbus. Not only that, but imagine it persisted, with flat earthers being as numerous today as atheists. While they aren't quite so numerous, flat Earthers do still exist, and it can actually be a helpful critical thinking exercise to listen to them. One of their most compelling arguments is fairly simple: "Where is the curve"?
Generally speaking, though the Earth is round, we experience it as if it was flat. It is a much bigger ball than we are a species. Therefore, in order to observe the curvature of the Earth, we need to do so from a distance that, for most people throughout history, simply wasn't realistic. They rarely climbed high mountains. They didn't fly in planes. They certainly couldn't send out rockets, or satellites, to see the Earth.
For this reason, "where is the curve" began as an intelligent argument against the round earth model. But as time went on, it ceased to be so. Aside from a wide range of evidence showing the spherical nature of the earth, these days we even have photographic technology. Flat earthers even use this, posting photos of the horizon, and asking that famous question "where is the curve?" Ironically, drawing a straight line over some of these photos even reveals the curve they are asking for! What would have been an excellent argument for the flat earth model 2,000 years ago is, today, one of the dumbest arguments you can make.
An equivalent to this is the so-called "problem of evil". The problem of evil is a famous atheistic argument against the existence of the Biblical God. If God is all powerful, He can stop any evil He wants. If God is all good, He would want to stop all evil. If God is all knowing, He would know both that evil exists and how/when to prevent it. Thus, the existence of evil, allegedly, precludes a God with all of these attributes, since such a God would immediately prevent any and all evil from ever occurring.
When this argument was first posed, it was a good one. Not good as in true, but good as in it made sense, and very likely caught a few of the faithful off guard. But just as "where is the curve?" has been answered millions of times, the "problem of evil" has been consistently and reliably answered. Not only is the existence of evil not a problem for the Christian faith, but to admit evil exists in the first place is to admit God does exist.
Understanding God's attributes
The first problem with the problem of evil is that it is based on a fundamental misunderstanding of God. It is true that God is all powerful, all knowing, and perfectly good, but the implications of this aren't what you would expect. In fact, atheists are often surprised to find there are things the Bible explicitly tells us God cannot do. Chief among these are lie (Titus 1:2) and deny Himself (2 Timothy 2:13).
Omnipotence
God's inability to deny Himself means He cannot cease to be God. That includes the inability to create a true contradiction. God is a logical being. Therefore, even a God who can do all things, cannot do that which is not a thing. He can make a virgin pregnant, because pregnancy is a thing, but He cannot make a virgin who has had sex, simply because the act of having sex makes one, by definition, not a virgin. Therefore, such a contradiction is impossible for God, not because He lacks some power, nor because there is something greater than He is that restrains Him, but because contradictions are simply not things. One might say nothing is impossible for God, and contradictions are nothing, therefore contradictions are impossible for God.
Of course, if this wasn't the case, atheists would have a much bigger problem to deal with, and Christians would have the easiest solution we never wanted. A god who could contradict himself would be able to be 100% evil and still remain absolutely perfect. This is not an argument I would ever want to make, and so I take God as I find Him: Sovereign over everything that is not Himself, but incapable of ceasing to be Himself.
Because of this, God cannot actually create a pre-determined choice. That's not to say He cannot influence choices. He can, like a master Chess player, influence free decisions, but He cannot create a being with free will that is always under His control.
It cannot be denied that God has given us free will. There are consequences for making the wrong decisions, but we do have the ability to make those decisions. In giving us this ability, God, who cannot contradict Himself, has given us the ability to choose evil. When we do so, this does not prove that He lacks one of His most famous attributes, but that He is, as the Bible tells us, incapable of denying Himself.
Omniscience
The obvious implication of God's omniscience is that God knew, even before He gave us free will, what we would do with it. Thus, atheists argue, God is still responsible for evil simply because knowing it would be the result of creation, He created anyway.
I like to pose a simple response: If you have a child, will it die? The answer is yes. Every human being will die, and unfortunately, many parents even outlive their children. Yet, we do not charge such parents with murder (unless, of course, they did murder their children). If you have a child, and that child dies of some disease at the tragically young age of 7, you don't go to jail. Why? Because knowing a child will inevitably die is a strange reason not to give it life. Life is a beautiful gift even in this fallen world, and so having children is a wonderful thing to do.
An atheistic parent knows that their child will live, but will one day die. God knows that His children will die, then He will grant them eternal life. Every Christian who has ever died will spend eternity with God in glory. Every day, week, month, year, century, millennium, will be devoid of any suffering, each filled with only joy. The greatest of all parents cannot offer their child so great a joy in their whole life as God will grant His children the very first minute in the Kingdom of Heaven. If that is the goal for this temporary suffering, how can God possibly be blamed for creating us?
Of course, an atheist might still complain about Hell. The devil, his angels, and the impenitent, will all suffer there, for eternity. But even this argument does not hold up, simply because everyone in Hell deserves to be there, and will suffer nothing there that their sin has not earned them. Furthermore, while God knew who would go to Hell, He did not force them to go there. For the devil and his angels, the simple solution would have been to remain in righteousness. They had the choice not to rebel; their rebellion was their choice, and theirs alone. For the people, not only does the same apply, but God actually did extend the same grace He extended to Christians to them.
As an example, let's take Christopher Hitchens. Christopher Hitchens made a career rebelling against God. He took his lies and blasphemies to his unfortunate grave, and barring some deathbed conversion no one seems to know about, he is destined for an eternity in Hell. But did He have to go? No. In fact, Christopher Hitchens was in a better place than most people to know Jesus. Who has more access to information than a popular atheistic apologist? Christopher Hitchens could easily have repented, and his excuses not to do so are significantly less than the average man.
God knew that Christopher Hitchens would go to Hell. And because of His sins, God is right to condemn him. But God did offer the chance to escape. If Christopher Hitchens had taken that, guess what? God would have known that instead! God's foreknowledge isn't what causes a choice to be made. Rather, the choice being made causes God's knowledge thereof. As Romans 8:29 says, "For whom He foreknew, He also predestined to be conformed to the image of His Son, that He might be the firstborn among many brethren." (Emphasis added). God didn't predestine Christopher Hitchens for Hell, and therefore know he would go. Rather, He knew Hitchens would go, and therefore predestined him for Hell.
But what if God simply never created Hitchens? The simple fact is, we do not, and cannot be expected to know what sort of butterfly effect that would have. Maybe, without him, more people go to Hell. Maybe the same amount go, but less end up in Heaven. Maybe it would make little difference, but frankly, God is well within His rights to create whoever He wants, and we have no right to tell Him otherwise. All answers are equally valid.
But there is a less obvious implication of God's omniscience that we, and atheists in particular, tend to miss: It means God knows more than us. That not only means He has thought of things we haven't, but even that He has thought of things we couldn't. What if there's a reason God allows evil that not even the wisest of Christian apologists knows? Put another way, let's suppose an atheist dies and finds out the hard way that there is a God. Is that atheist really going to stroll into His courtroom and say "ok, I was wrong, you're real, but clearly you lack a few nuggets of wisdom, and I'm about to give them to you..."? Of course not! Read the book of Job and see how that worked out for him. Job wanted to plead his case to God, God showed up as a whirlwind, asked Job a bunch of questions, and Job repented of any and all doubts he had. Being without answer to a single of God's questions about something as low as the Earth, he realised he had no understanding of the things of Heaven. How much less can an atheist hope to speak against God?
Omnibenevolence
The greatest irony of the problem of evil is that, far from disproving the existence of God, anyone who makes it must actually admit God exists. Think of it this way: How can one say "there is a hole in that donut" without admitting the donut exists? Much like a hole, evil is not actually a created thing, but rather, it is the absence of good.
In Romans 4:15, Paul tells us "...where there is no law there is no transgression." You cannot break a law that does not exist. But a law cannot exist without a law maker. Furthermore, laws are abstract concepts. They don't exist in the physical world, like a rock. You can pick up a rock and say "this is a rock", but you cannot pick up a rock and see if it is ok to pick it up or not.
What that means is that not only does there have to be a God in order for an atheist to say evil exists, but even for them to identify what it is. If there is no God, an atheist must come up with his own definition of evil, but none of those ever hold up. Effectively, the argument becomes "God doesn't exist because He allows this thing I don't like". But since when has an atheist, or even a man, been the standard? Heck, we judge whole cultures, past and present. Human beings cannot be the standard of good and evil, if for no other reason than that we can't even all agree on what that is.
With that in mind, it's amazing that God's moral commands are benevolent in any way at all. With such unrestrained power, the restraint God does show is almost unthinkable. Certainly none of us would be as kind if we were capable of such feats. The commands God gives show His benevolent nature. Why is it wrong to kill? Because God is a God of life. Why is it right to forgive? Because God is a God of mercy. Why is it wrong to steal? Because God rewards diligence with dominion. Why is it right to give? Because God gives. "“You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’ But I say to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you,5 that you may be sons of your Father in heaven; for He makes His sun rise on the evil and on the good, and sends rain on the just and on the unjust. For if you love those who love you, what reward have you? Do not even the tax collectors do the same? And if you greet your brethren only, what do you do more than others? Do not even the tax collectors do so? Therefore you shall be perfect, just as your Father in heaven is perfect." (Matthew 5:43-48).
From this, we do see that evil shows the absence of God, but not from reality. Rather, it shows the absence of God from free willed agents who are designed to bear His image. Even then, the evil we commit is only possible because of the things God gave us for good. A lying tongue can only lie because it was designed to speak truth. One can only commit adultery because marriage is a beautiful thing. Feet which run to evil can only do so because they were designed to walk with God. Like our hypothetical donut hole, evil can only exist because good exists.
In fact, this is the very reason free will exists. Love that is forced is not true. We have never been more capable of showing this. As technology increased, we have the ability to create virtual beings. And we do. Who doesn't have Siri, Cortana, or Alexa, programmed into their smartphone? Even these are not alone. Several apps present artificially intelligent characters who are surprisingly capable of engaging in conversation. Some of these are designed as virtual friends, and bizarrely, some even have the option of becoming romantic partners. But this isn't real. Even if technology develops to the point where we can put such minds into real human bodies, the resulting people wouldn't even be people. Sure, they could say they love you, because they have been programmed for it. But given the choice, which would you prefer? A real person who chose to love you, or an artificial intelligence with no choice? In His wisdom, God chose the former, preferring penitent sinners over pre-programmed robots.
Peter's simple answer
With all that in mind, the simplest answer to the "problem" of evil is found in the pages of scripture. Let's read the whole of 2 Peter 3:
"Beloved, I now write to you this second epistle (in both of which I stir up your pure minds by way of reminder), that you may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us, the apostles of the Lord and Savior, knowing this first: that scoffers will come in the last days, walking according to their own lusts, and saying, “Where is the promise of His coming? For since the fathers fell asleep, all things continue as they were from the beginning of creation.” For this they willfully forget: that by the word of God the heavens were of old, and the earth standing out of water and in the water, by which the world that then existed perished, being flooded with water. But the heavens and the earth which are now preserved by the same word, are reserved for fire until the day of judgment and perdition of ungodly men.
But, beloved, do not forget this one thing, that with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance. But the day of the Lord will come as a thief in the night, in which the heavens will pass away with a great noise, and the elements will melt with fervent heat; both the earth and the works that are in it will be burned up. Therefore, since all these things will be dissolved, what manner of persons ought you to be in holy conduct and godliness, looking for and hastening the coming of the day of God, because of which the heavens will be dissolved, being on fire, and the elements will melt with fervent heat? Nevertheless we, according to His promise, look for new heavens and a new earth in which righteousness dwells.
Therefore, beloved, looking forward to these things, be diligent to be found by Him in peace, without spot and blameless; and consider that the longsuffering of our Lord is salvation—as also our beloved brother Paul, according to the wisdom given to him, has written to you, as also in all his epistles, speaking in them of these things, in which are some things hard to understand, which untaught and unstable people twist to their own destruction, as they do also the rest of the Scriptures. You therefore, beloved, since you know this beforehand, beware lest you also fall from your own steadfastness, being led away with the error of the wicked; but grow in the grace and knowledge of our Lord and Savior Jesus Christ. To Him be the glory both now and forever. Amen."
While not directly addressing the problem of evil, in his address of Christ's apparent slow return, Peter gives a clear reason God is not stopping evil yet. Though being well aware of the problem, God's love for sinners prompts Him to hold off using His power. A time will come, and not at an hour convenient for us, when He will put a stop to evil. But for our sake, He can afford to wait. He can wait a day, He can wait a thousand years, it makes little difference to Him. But in the end, a Kingdom is coming in which only righteousness dwells.
That Kingdom will actually be full of people like Paul. Listen to his testimony: "And I thank Christ Jesus our Lord who has enabled me, because He counted me faithful, putting me into the ministry, although I was formerly a blasphemer, a persecutor, and an insolent man; but I obtained mercy because I did it ignorantly in unbelief. And the grace of our Lord was exceedingly abundant, with faith and love which are in Christ Jesus. This is a faithful saying and worthy of all acceptance, that Christ Jesus came into the world to save sinners, of whom I am chief. However, for this reason I obtained mercy, that in me first Jesus Christ might show all longsuffering, as a pattern to those who are going to believe on Him for everlasting life. Now to the King eternal, immortal, invisible, to God who alone is wise, be honor and glory forever and ever. Amen." (1 Timothy 1:12-17).
Paul was evil, so much so that he actually had Christian blood on his hands. It would have been entirely just for God to send Him to Hell. But in His mercy, He brought Paul into the Church, and even those whom he killed would have rejoiced as their murderer entered the Kingdom as their brother. God's patience enables hundreds, even thousands of people every day to receive that same mercy.
And my atheist friend, that could include you. Today, if God should roll up His sleeves and say "this is the day", where would you go? But perhaps this article has given you a few things to think about. Maybe you still won't convert, however. Maybe you won't even think about God again for another year. It could even be a deathbed conversion for you. 10, 20, 30 years from now, you might still be rebelling against the God who gives you breath. But what about on year 31?
Every second counts. Today is the day of salvation, but so was yesterday. You are not promised tomorrow, but God may yet grant it, not because He cannot stop evil now, but because He has motive to do the most good thing of all: Forgive.
Conclusion
When it was first posed, the problem of evil may well have seemed like a powerful argument. Today, however, it is so easily refuted that not even a rookie has an excuse. If you do not know at least one answer to the problem of evil, you haven't put any thought into your worldview. And if you speak on things you haven't thought about, what other description can you accept but "fool"? The problem of evil is a foolish argument, not by virtue of its nature, but simply because only the ignorant and the deceptive could ever use it. But no one should be ok with deception.