When the Gallup organization first polled Americans asking, "Do you believe in God?", 96% of Americans said, "Yes". That was in 1944. In 2022, that number had fallen to 81% (tinyurl.com/4b9y732n). Gallup has also shown that belief that humans originated from a godless process of evolution has increased from 9% in 1982 to 22% in 2019 (tinyurl.com/cr994kw9).
This means we are all going to interact with atheists more in our daily lives than ever before. How do you talk to those who don't believe in God's existence? How do you share the gospel with them?
There are many Christian apologists, scientists, and philosophers who can argue more convincingly than I can for the existence of God, the truth of the Bible, and the reality of Jesus being the Messiah.
But you don't have to be a trained academic to believe these things or share them with an atheist. The Bible addresses the issue of denial of God's existence in many places that can inform our response to atheists and atheism.
The External Evidence
Beginning in Genesis 1 and 2, the Bible teaches us that God is the creator of the heavens and the earth and all that is within them, including us. These two chapters show that God designed the lights in the sky to benefit us (1:14-18), plants to feed us (1:29), and all the rest of creation to be subdued by us (1:28).
Those chapters teach that God's creation of the universe shows His existence, power, and purpose. His power is revealed in the ability to create all these things with such massive scale and minute detail. His purpose is revealed in that he lovingly orchestrated and sustains creation, from the smallest bacteria to massive stars, to sustain, multiply, and assist human life.
This is what Paul refers to when he writes, "For since the creation of the world His invisible attributes, both His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. For even though they knew God, they did not glorify Him as God or give thanks, but they became futile in their thoughts, and their foolish heart was darkened." (1:20-21) This means that people can see that God has divinely and powerfully organized the universe in such a way that sustains their lives. They should give thanks to Him for that. But their foolish hearts futilely refrain from doing so.
Christian philosophers call this the "teleological argument". Telos means a goal. In contrast to atheism's proposal of a random and undirected universe, the teleological argument states that the vast and detailed operation of the universe shows the hand of God. This argument is as simple as noticing how livable the earth is: that the human population has jumped from just 2 people to nearly 8 billion people today. But it also can be seen in the fine tuning of the universe (which you can start to explore here: tinyurl.com/3u4sh3vz). Whether you're using a microscope, a telescope, an ophthalmoscope, or the naked eye, you can perceive the order, detail, and complexity of God's creation.
In addition to this, God designed the human mind in a way that is capable of noticing this and responding to Him. This is what I call the internal evidence for God.
The Internal Evidence
But there's another way Genesis 1-2 helps us to see God's role as creator. Genesis 1:27 says that God created us in His image. God created in His image so we could relate to him in ways the rest of the creation can't. This is why God holds people uniquely accountable to give him glory, thanks, worship, and service (Romans 1:21, 25). Animals can't do those things because God hasn't given them that capacity.
How can we see God's image in ourselves? We can see that we have a unique capacity for relationships, creativity, morality, and spirituality. Animals relate to other beings based on instinct, they don't create outside that instinct, their moral framework is instinctive, and they lack any spiritual capacity.
Humans, on the other hand, are capable of forming and conducting relationships based on shared values that transcend common human instinct. We also communicate within those relationships with a capacity and complexity of language and emotion that dwarfs that of any other animal.
Creatively, humans compose works like music, songs, dances, poetry, fiction, and non-fiction texts that are individual expressions unique from those produced by other humans. It is normal for birds of the same species to have the same song. But when humans copy the words of others, we often consider it plagiarism unless credit is given to the individual who composed it. We recognize that each person has unique thoughts and a unique ability to express them.
Morally, human beings write, debate, and apply laws in a manner totally unprecedented by any animal, even the most intelligent. While animals may have instinctive behaviors as individuals and groups, they don't propose laws, vote to form congressional bodies, have vigorous debates, and form courts to interpret and apply laws. Most interestingly, human beings understand and ascribe to codes of law which they choose to violate.
Last of all, God has given humans an innate desire to worship. Worship is a high form of recognition where someone ascribes significant or ultimate worth to something else. No other creature creates sanctuaries, hymns, religious texts, or psalms to relate to or worship God or any other thing. Even humans who say they don't believe in God still enjoy singing worshipful songs and treat other things in a manner which meets the criteria of worship.
Naturalism, the belief that the physical world is all that exists, is foolish (Psalm 14, 53). It's foolish because it misses the testimony of His orderly creation which sustains us. It's foolish because it ignores the unique image in which He has made us. The external and internal witnesses for our Creator don't merely tell of His power and divinity; they also speak of the depth of His love for us and desire that we respond to Him in praise. The more we embrace the testimony of His creation outside of us and within us, the more we will see our need for forgiveness and redemption from our sins through Jesus Christ.
When you talk with an atheist, the external and internal evidence from our Creator are two ways to help bring wisdom to someone who is deceived by folly. We are sinners who have denied God our worship, thanks, and service, though He thoughtfully designed a world to sustain us and lovingly designed us to worship Him. From that point, the gospel can be all the more clear: Jesus came and died for our sins, was buried, and rose, all according to the plan God foretold in the Old Testament scriptures.