Morality is one of the fiercest battlegrounds in the realm of apologetics. From the moral argument made by Theists to the evil Bible argument made by highly inconsistent atheists, you will find a wealth of discussions about morality. But the good thing about the evil Bible argument is that it actually allows us to springboard into the moral argument, meaning the moral argument can be both an offensive and a defensive strategy.
Ultimately, the eternal nature of God means He must necessarily be free from all external moral obligations. As the Lord asks Job, "who has preceded me, that I should pay him?" This, He follows up with "Everything under Heaven is mine." Now, setting aside the fact that God has every right to "pick His own locks", so to speak, every atheist must answer one fundamental question: Who has preceded God that He should pay him?
See, any moral standard must come from somewhere. Laws require legislators. You cannot say "that is illegal" if there is no government. Thus, in order to bind any being to any moral standard, you must identify what that standard is, and what binds that being to it.
Yet, God precedes everything. He precedes light, He precedes the heavens, He precedes the Earth, He precedes the ground, He precedes the sun, He precedes life, He precedes man and angel alike. Nothing that is not God exists without God. And so what binds God to any moral standard? All authority comes from God, and thus belongs to God, which necessarily prevents any charges being brought against God.
Atheists, therefore, automatically lose any and all attempts to gain the moral high ground over God. They are therefore stuck between a rock and a hard place. The rock is that any attempt to call God evil is nothing short of an appeal to one's own subjective opinions. Thus, the evil Bible argument is as pitiful as saying "Jesus drank wine, but I'm teetotal, therefore the Bible is wrong". The hard place is that the evil Bible argument is circular reasoning. In order for the evil Bible argument to work, you must first prove that an alternative worldview to Christianity is true before you can make the argument, which means the evil Bible argument concludes with its own premise.
But it gets worse than that for atheists, because even if you remove God from your worldview, you are still required to prove the existence of a moral source before you can make moral claims. But this is something an atheist can never do. See, if there is no God, that leaves a huge void to be filled. Who fills it? If you're an atheist, you must necessarily believe we fill that void. But then we get back to the ice cream thing. Humans differ as much morally as we do in our tastes. Atheists, radically so. There are as many radically different views among atheists as there are between Theistic religions, and with no codified scriptures to say to an atheist "thou shalt" and "thou shalt not", atheists are free to change on a whim. As I once said, "in Christianity, murder is morally wrong. In atheism, murder is morally different."
Which brings us to the heart of the moral argument. See, the evil Bible argument contains three important elements: 1. A correct understanding of the value of human life. 2. A failure to see the "bigger picture". 3. An incomplete understanding of God's authority and justice.
Having already looked at number 3 in the article above, let us now turn to the first element: A correct understanding of the value of human life. As we have seen above, moral values can only exist in a Theistic worldview, yet atheists correctly recognise that moral values do exist. They live their lives as if moral values exist, and they even argue as if moral values exist. God has given us this wonderful gift known as a "conscience". That is, we have basic moral instincts ingrained into us from the day we are born. This presents atheists with yet another dilemma. They can claim that these moral instincts are mere delusions, but it's more likely that a "good person", for lack of better term, will admit that these moral values are real.
Both of these options are equally terrifying. If moral values are just delusions, then all it takes is for enough people to figure that out before society collapses, and human kingdoms become as anarchistic as the animal kingdom. Furthermore, all actions, whether we perceive them as good or bad, are ultimately futile. We can do "bad" and escape without consequences. We can do "good", and no matter the expense to us, receive no return.
By contrast, if those moral obligations are real, they are coming from somewhere. And if they're coming from somewhere, this naturally brings with it a certain amount of accountability. Particularly if that moral source is God, because His word says two very scary things: "all have sinned and fall short of the glory of God" (Romans 3:23) and "For God will bring every work into judgment, Including every secret thing, Whether good or evil." (Ecclesiastes 12:14).
Which brings us to the second element: A failure to see the "bigger picture". If there's one thing Christians and atheists agree on, it's that death is an inevitability. Whether you die a tragic death at a young age, or peacefully in your sleep at the end of a very happy life, the fact is you will die. If there is no afterlife, that doesn't matter. Whether you're an atheist, a Christian, or something else entirely, you will simply cease to exist, and ultimately, nothing you have done will matter.
But what if Christianity is true? In this case, perfect justice is done. This is bad news for sinners. But what if it didn't have to be? What if, instead of punishing us for our sins, as we deserve, God instead emptied His wrath upon His own, innocent Son? Logic dictates that sin can only be punished once. Once a debt is paid, the debtor is released. Well, as it happens, this is exactly what God did. Jesus Christ walked the Earth as a man, and during His life, He never had a single thought towards sin. Yet, He died as a sinner ought, and rose from the grave on the third day. This beautiful act of self sacrifice enables us to be reconciled to God. But only through faith. If we are to receive salvation, we must confess our need of it, and the method by which it was bought for us. Therefore, those who confess with our mouths the Lord Jesus, and believe in our hearts God raised Him from the dead, will be saved. Everyone else, unfortunately, will receive a punishment fitting of their crime. Accept God's free gift to you today, because you may not be around to do so tomorrow.