But, well, Yes.
(look at the little comic below, and then proceed reading)
Whenever someone asks me this question, I always have to ask: what do you mean by “need” and what do you mean by ‘good’ or ‘religion’?
The little comic above is so misleading I don’t know where to start. The rhetoric that religion is unnecessary for moral living simply begs so many questions that it is sometimes alarming that we cannot see right through its naive assumptions.
First, let’s address what this question means by “need.” The ‘need’ in view in this question can be understood in two ways: epistemically or metaphysically. If the epistemic sense is in view, then the question becomes more precisely put this way: “do we need to explicitly believe in a particular religion to be a good person?” Put in this way, then of course the answer is no. There are plenty of people who repudiate the major religions of the world who live relatively moral lives. This observation, though, is uninteresting and trivial. The terribly misleading and naive picture above exemplifies the question in the epistemological sense. It is the second sense of “need” that must be discussed with greater depth.
For the second sense to be discussed, however, we need to make a distinction between “Religion” – which pertains to actions and beliefs and institutions – and God. I want to put the question this way: “Do we need God to live a moral life?” If the second, metaphysical, sense is in view then the question becomes put this way: “Is the existence of God necessary to account for the ability to live morally, and for the existence of morality?” – Notice such a question is distinct from the epistemological question “Do you need to believe in God to live morally?”
So, if the second, metaphysical sense is in view, the question becomes much more pertinent and weighty – and I believe the answer to the question is without ambiguity a resounding yes.
Without the existence of God, we cannot account for the existence of morality. A godless, naturalistic universe makes for an unnatural home for the existence of morality. If all that exists is merely physical, how can the moral spring to be? And if morality stems from an impersonal universe, how can human beings be simply obligated to do the good, and not the evil? What is goodness in a naturalistic universe? All we can say at the end of the day, perhaps, is that goodness is that which is invented by human societies – but when two human societies contradict on to what they think goodness is, we would have no basis on which to adjudicate which human society has the proper definition of goodness.
Let me press this further. In fact, if the universe is naturalistic and godless, it will be wholly unexpected that the universe will produce creatures that are capable of living morally. Morality is a universal law that binds all human beings – but in the atheistic, naturalistic universe, all that exists is material. Morality is immaterial. So, on the naturalistic ground, morality, by definition, do not exist. Put it another way, the fact that we know there exists such a thing as morality points us away from naturalism and towards the existence of God. Naturalism cannot account for the existence of morality, of obligation, of praise, of evil. They have no standard to appeal to. They have no metaphysical resources to ground morality.
In fact this is exactly what is taking place. Even when naturalists might profess the denial of God, they depend on the existence of God to live morally. In other words, naturalists live morally in spite of their professed disbelief in God. In other words, when naturalists live morally, they exemplify who they are as made in the image of God – they cannot help but live morally because of who they are metaphysically despite of what they profess to believe epistemologically. So, when a naturalist does good he cannot account for the good that he does – and the fact that he does good reveals the necessary presupposition behind that good: the existence of the Triune God. Morality in humanity is a reflection of the law that God had prescribed for all people. Impersonal things do not obligate people. Only Persons obligate people. If the universe is at bottom impersonal, then there can be no obligations. Obligation and impersonality cancel out each other. Obligation and Personhood, by contrast, imply one another in an organic correlation.
So the next time we see naturalists and agnostics doing good, we are to be reminded that they too are made in the image of God, and the morality that they do reflect the very God that they deny, and on whom they depend.
Likewise, to say that our action determines whether we are good or bad simply begs the question: how can our action determine our goodness when we would have no basis to determine what goodness even is without the existence of God?
Thus, also, goodness is defined by what God says: insofar as nonbelievers deny God, the good that they do, though seemingly good in the eyes of men, cannot be good in the eyes of God. This, again, further points to our need to repent, and believe in Jesus Christ, on whom all our goodness depends.
For further reading, see my fictional letter to a naturalist