An atheist's only defence against the moral argument is to misrepresent it. One of the ways they do so is to claim that we don't need God to justify morality, because there are ways to figure out how we should run our lives and our societies without Him. If atheists would only learn the difference between "God is required to give morality meaning" and "God is required for morality to give morality sense", the argument from morality would stand strong.
Obviously, one does not require belief in God in order to reap the benefits of living as if He's there. If you believe your car is powered by an army of hamsters running around on wheels, you're still going to be capable of driving it. God does not give stupid laws, and therefore living by those laws, regardless of how much faith you have in the God who gave them, will work.
But the question is, work for what? Atheists have two problems, the first being how to establish a goal, and the second being what's the difference between varying ways of achieving it?
First, how do we establish the goal? It's one thing to say we don't need God to tell us how to live long, happy, and healthy lives, it's another thing to show that long and happy lives are a good thing. If life is an accident, where does its value come from? And a more pressing question, whose happiness and length of life? How many people gain happiness by cutting short the life of a pig and devouring its flesh? No atheist has ever been able to explain why any life would be objectively valuable if it wasn't created by God. By contrast, many of them admit it simply couldn't be. I've seen atheists admit they can't explain why their lives are more valuable than the animals they eat. Most of them prefer to avoid the question all together.
Furthermore, there is often more than one way to achieve the same result. For example, you don't have to outrun the tiger, you just have to outrun your friend. Morally speaking, we would regard a man who trips his friend to save his own life as a coward, and probably a murderer. If, however, that same friend sacrifices himself without being tripped, the friend is regarded as a hero. The end result is identical: The same man survives the tiger attack, and the same man dies in it. But the moral implications are the exact opposite. One is selfishness resulting in murder, which is evil, the other is sacrificial love, which is the highest form of good.
Ultimately, the Bible answers both questions. What is the goal, and how do we get there? The answer to both is the same: The goal is obedience, and the means is obedience. Alas, man is naturally very disobedient. We rebel against God in many ways, and as a result, we must be punished. But God isn't willing to punish man. His solution? Transfer the punishment elsewhere, namely to Jesus. Jesus died so we don't have to. Through faith in His death and resurrection, our disobedience can be forgiven, and when we are resurrected in the end, we get to spend eternity with our Creator.