In his New York Times bestseller Good Without God, Greg Epstein points out a fascinating statistic: “Even if we exclude the approximately half of non-religious people who say they believe in some form of 'spirit' . . . there are still more than half a billion people in the world who live without belief in God.”

Impressive, but not surprising. Particularly in modern Western society, a growing contingent no longer affiliates with traditional religions, instead preferring science as an alternative and—dare we say—superior source of truth and knowledge. The question “Does God exist?” is no longer as relevant as it used to be, and a new default question takes its place: “Since God doesn't exist, how should we live?” Such an environment simply assumes deep and abiding skepticism regarding the Bible's authority and truthfulness, and therefore, its applicability.

At the forefront of this movement are the humanists. According to Epstein, “Humanism is being good without God,” which, at the core, is about “taking charge of the often lousy world around us and working to shape it into a better place.” It's a tantalizingly compelling rally cry for our generation, and countless individuals inspired by this vision of a just society for us and by us have been working tirelessly for goodness, human flourishing, the end of suffering, and equal rights worldwide.

But none of these goals is new to Christianity; in fact, many humanist and Christian aims are in complete agreement, and it's quite feasible for the two groups to work in tandem to find solutions to the myriad problems facing our world. Which begs the question: “If we can be good without God, why do we need God at all?” Might as well get rid of the redundancies.

Light of the World

Before we throw out the baby with the bathwater, however, we need to recognize that “good without God” is not a statement about the existence of God; it is an indictment against Christians. Such ideologies gain popularity in part because Christians so often fail to turn the other cheek or go the extra mile or love our neighbors as ourselves. Unless accompanied by compelling examples of Christ-like behavior, apologetics or theology will not convince many people that there is indeed one true and living God who will some day make all things new.

But what a difference it would make if they would see the fruit of the our faith, evidence of the Holy Spirit's work in our lives. As the fragrance of Christ to a lost world, followers of Jesus diverge from the ways of the world as we live with a mission and purpose informed by the gospel message.

And so we find that Jesus' words in Matthew 5:14-16 ring ever so true in our day and age:

You are the light of the world. A town built on a hill cannot be hidden. Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. In the same way, let your light shine before others, that they may see your good deeds and glorify your Father in heaven.

The light will only shine if our hearts have been transformed by the love and grace shown to us through Christ's life, death, and resurrection. Gazing upon Christ, his work in our place, and our justification before God, our hearts melt with gratitude and joy and we devote our lives to spreading the gospel as we await Jesus' return, when he will renew his creation.

Editors' note: Join Redeemer Presbyterian Church on Sunday evening, November 17, as Greg Epstein talks with Tim Keller about the implications of C. S. Lewis's classic essay, “On Living in an Atomic Age.” A time of questions and answers will follow. This event commemorates the 50th anniversary of Lewis's death. Prior to the conversation, Max McLean (Listener's BibleThe Screwtape Letters) will perform a dramatic rendition of “On Living in an Atomic Age.” You can watch this special event via live webcast on Sunday at 7 p.m. EST.