Specifically, in Hunting Magic Eels I make the argument that the single greatest challenge facing the church in the West is the moralization of faith. That is to say, the whole point of faith, religion, God, and the church--the whole smash--is to be a kind, loving, and decent person.
In many ways, you could argue that "the Great Moralization" of the West--that we all want to be kind, loving, and decent people--was the singular and particular achievement of Christianity. See Tom Holland's book Dominion for a historian making this argument.
And yet, this moralization has become a challenge for Christianity as well. As I point out in Hunting Magic Eels, when being a kind, loving, and decent person becomes the goal of faith it also quickly becomes clear that you can be a kind, loving, and decent person without God, faith, religion, or the church. In fact, with so many notorious examples of Christians not behaving as kind, loving, and decent people it can seem that God just makes people worse. It's a double-whammy. God is both irrelevant and toxic. Best than to jettison the religious baggage to focus--in a secular, irreligious, and humanistic way--on simply being kind, loving and decent. This is a less treacherous and more straightforward path to reaching the desired goal.
As I said, this development, the moralization of faith, is the single greatest challenge facing the church. I deal with it all the time in my context as a college professor. For example, I recently had a conversation with a college student, a Bible and Ministry major, who was struggling with their faith and calling. Why? This exact issue. As the student shared, "I have good friends who are atheists who are amazing people. They are more loving than most of the Christians I know." And this observation--that some atheists are more loving than some Christians--was calling everything into question. Clearly, this is a shaky and unsustainable way of thinking about God and faith. And yet, it's the way an entire generation of young Christians now look at the situation. Being a good person is the entire point, and it's obvious you don't need God to do that.
Now, I do want to quickly interject something here. A small point. The observation "I know atheists who are more loving than Christians" is widely shared and repeated. You hear it all the time. And it carries a lot of rhetorical force. It wins a lot of arguments. And yet, it's a weird and highly selective argument. For example, I could just as easily say, "I know Christians who are more loving than atheists." This is also demonstrably true. That is to say, if you pick a loving atheist of your acquaintance and compare them to the worst Christian you know, it's hard to know what such a comparison is saying. Because you could do any number of comparisons to draw different conclusions. There are loving atheists and loving Christians. There are awful atheists and awful Christians. I'm not sure what making selective comparisons between any pair of persons drawn from these groups is supposed to tell us.
Still, it raises the question that if an atheist is found in the kind, loving, and decent bucket do they need God, faith, and the church? Or is being kind, loving, and decent enough?
I think a lot of us, especially progressive Christians, would say being good is good enough. Let's leave the good people alone. Especially given all the bad apples in our own group. As it says in 1 Peter 4.17, let the judgment of God begin first with the household of God. Let's pick the beam out of our own eye before picking at a speck in the eye of an atheist. As Paul says in 1 Corinthians 5.12, what business is it of ours to judge the world? Our job, says Paul, is to judge those on the inside of the church. This is very good advice.
Plus, as I noted above, if modern goodness, in the West, is the product of the Christian revolution then every good person is following the path of Jesus. Every time a person cares for a neighbor or extends kindness on the street that's the leaven of Christ working secretly in the world.
And yet, given all the questions I get from my college students, I also think it's worth thinking a little bit about how even good people might need the Lord.