Atheists don’t believe that God exists, so why would we address atheism as if it's a religion? Aren’t atheists in a different category than, say, Hindus, Muslims, and Buddhists? Yes and no.
Atheists are obviously different from other religions in certain ways—they don’t bow down to statues, read sacred texts, or recite prayers. So in terms of what we normally refer to as religion, no, atheists don’t fit the profile. But if we think in categories like worship and idolatry, then yes, it’s appropriate to study atheism as we think about engaging different belief systems around the world.
Romans 1:23 teaches us that all people exchange the truth about God for a lie, choosing to worship the creation rather than the Creator. That includes atheists. John Calvin was right when he said that man’s sinful nature produces a “perpetual factory of idols.” Undoubtedly, an atheist’s idol will look different than a Buddhist statue. The atheist may rely solely on his own reason to decide what’s true, he may give himself fully to physical pleasure, or, as Jesus put it, he may choose to serve money rather than God (Matthew 6:24). God’s assessment is still the same: Many atheists have rejected God simply because they don’t like the God revealed in Scripture. Regardless of the reason, atheists are no strangers to idolatry, and God’s assessment is still the same:
"All worshipers of images are put to shame,
who make their boast in worthless idols;
worship him, all you gods!" (Psalm 97:7)
Though they wouldn’t admit it, many atheists have rejected God’s existence simply because they don’t like Him. Regardless of the reason, atheists are no strangers to idolatry. Like Hindus and Muslims, they have their own forms of worship.
Knowing how atheists are similar to people of other religions does not mean we shouldn’t get to know the specifics of what they believe. That’s the whole point of this upcoming Secret Church—to engage people of other religions more effectively with the gospel. However, we need to realize that atheists need the same message that we share with every unbeliever, namely, the gospel of Jesus Christ. Christ is the Savior of illiterate animists as well as educated atheists.
In this upcoming Secret Church, David Platt will discuss some practical ways to engage atheists with the gospel. In the meantime, be thinking of those you know who have rejected the idea of God altogether. Pray for them, and instead of trying to avoid conversations about God because the topic seems irrelevant, trust the power of the gospel to topple their idols of choice.
-- For more on atheism (the belief that there is no God), agnosticism (the belief that it is impossible to know if there is a God or gods) and secular humanism (the organization of atheistic or agnostic beliefs into an ideological system) see the section on atheism in Secret Church 16, “A Global Gospel in a World of Religions.”
John Calvin, Institutes of the Christian Religion, Vol.1, p.108 (1.11.8).