When asked why he chose to write the book – Timothy Keller: His Spiritual and Intellectual Formation – in this way, Hansen’s answer is simple. Because that’s how Tim tells his own story.

“If you ask him about himself,” Hansen explains, “he tells you about C.S. Lewis or about something he learned from Jonathan Edwards.”

This reveals two unique truths about Tim Keller. Firstly, this former New York pastor who founded the megachurch Redeemer (which grew to over 5000 attenders by the time Keller stepped back as lead pastor in 2017) owes much of his spiritual formation to British theologians. His key influences include John Stott, Martyn Lloyd-Jones and J.I. Packer, rather than American evangelical giants like Billy Graham and Carl Henry. “That gives you a bit of perspective on why he has resonated. He’s clearly an American, but he doesn’t strike people as parochial in that way,” says Hansen.

“I’m not sure Tim is somebody who really enjoys a whole bunch of attention.” – Collin Hansen

Secondly, despite his massive influence as a pastor, as author of over 30 books (including the New York Times bestsellers The Reason for God and The Prodigal God) and as founder of church resourcing movement The Gospel Coalition, Keller is uncomfortable taking centre stage.

“When you’re talking with Tim about something, often you almost feel him physically moving to start to comment on the situation,” Hansen explains. “So imagine you’re looking at him preaching. Number one, he’s always pointing to Jesus. But second, it’s almost a way of him stepping to the side and letting you hear from someone else. Because at some level, I’m not sure Tim is somebody who really enjoys a whole bunch of attention.”

Tim Keller, the preacher

Some criticise Keller for not resembling the stereotypical American evangelical, especially because of his political inactivity and “excessively” evangelistic approach.

Keller’s lack of political partisanship and his evangelistic focus both stem from a desire simply to preach the gospel, says Hansen – to “strip away the things that make people upset at Christians that are not the gospel, so that they can be properly offended by the gospel.”

Who does Hansen credit as the greatest influence on Keller spiritually and intellectually? Kathy Keller.

Perhaps Keller’s most resonant presentation of the gospel is his explanation of Luke 15:11-32. Often called the Parable of the Prodigal Son, Keller thinks of it as the parable of two sons, with both communal and individual implications. Some people and some churches incline toward the older brother, others toward the younger.

“What’s interesting,” Hansen notes, “is that Tim defies that logic. He is himself both [sons].” Before his conversion, Keller abandoned the beliefs and values of his overbearing mother. But he is also a textbook rule-follower, known by his family members as ‘Boy Scout.’

“I think you see both dynamics in his life,” Hansen continues, “which has allowed him to speak not only in New York to the Wall Street banker, but also to the artist. That’s not something that a lot of other people have been able to pull off. But it’s more effective with somebody who really has a sense of their need for grace in both directions, because of their licentiousness, but also their legalism.”

Hansen sees Keller’s introspectiveness as helping hearers “to understand themselves in light of the gospel – the severity of their sin, but also the overwhelming goodness of grace.

“I think if we wanted to talk about his one legacy,” he concludes, “he’d probably want us to read his book The Prodigal God – just that basic story of grace.”

Tim Keller, the man

In a book about C.S. Lewis and Jonathan Edwards, who does Hansen credit as the greatest influence on Keller spiritually and intellectually? Kathy Keller.

“I suppose at one level, it wouldn’t be novel for me to say that somebody’s spouse was their biggest influence. But I don’t think that explains any of the distinctiveness of Tim and Kathy together.”

The Kellers got to know each other and got married during seminary – an uncommon combination of two people independently on the same intellectual and ministry track. But Hansen emphasises “how much of a dynamic figure [Kathy] is on her own.”

Not growing up in an evangelical home, the only Christian literature Kathy knew was C.S. Lewis. In fact, she thought she was his only fan. At 13, Kathy was one of the last people ever to correspond with Lewis, writing to encourage a man she thought was an unknown author. A couple of years later, she travelled to his house and spoke with his brother. Soon after that, John Guest, a significant figure in the Jesus Revolution, called Kathy the most brilliant youth organiser in Pennsylvania during a huge youth revival in the area.

Hansen chuckles approvingly at Kathy’s boldness when she told Tim, “Once you’ve broken up with the other girl, we’re either going to be an item or we’re not going to be friends. But I’m not going to sit around and wait for you to figure this out.

“She’s always had that ability to help, assist and support, but also to challenge in ways that are really beneficial to Tim and compatible with him,” says Hansen.

“I would love the church to recapture his ability to learn from people that we disagree with …” – Collin Hansen

Discussing personal relationships, Hansen also pulled back the curtain to describe Keller’s impact on him. Hansen first met Keller in 2007 and began working with him at The Gospel Coalition in 2010, where Hansen now serves as Vice President for Content and Editor in Chief.

“I’m not by any stretch a clone of him,” Hansen explains. Keller lives in New York City; Hansen in Alabama. Keller is a Presbyterian, Hansen a Baptist. Keller hates conflict; Hansen is an editor.

“There are a lot of differences, but I think that’s one of the easiest ways to honour Tim. I have never heard him say a critical thing about another person. It’s not because he doesn’t have opinions; it’s just that he finds what he can affirm in other people and learn from them.

“I would love the church to recapture his ability to learn from people that we disagree with on other things. We would be a more harmonious church if we could affirm what’s good in somebody else, while acknowledging our disagreements with them. I just think that’s a very healthy way to be a Christian. It builds up the unity of the church, while preserving the integrity of the gospel. We’re commanded to do both.”

“My wife and I would never want to go back to the kind of prayer life and spiritual life we had before the cancer. Never.” – Tim Keller

Keller’s desire to learn from every possible source stems from an inexhaustible and infectious curiosity. Hansen laments that one story came to him from Keller’s close friend Graham Howell after his book was published. On their many beach vacations in South Carolina, Howell recounted that Keller would bring suitcases of books. His brother-in-law, Jim Pickard, described sitting next to Keller on the beach, asking a question and receiving an hour- long response. “You might be kind of annoyed with somebody who would do that on your beach vacation,” Pickard said, “But it was pretty interesting!” Other friends described how on trips around the United States and overseas, Keller recounted the history of each region after spending the previous evening reading books about it.

“He’s a learner and a teacher,” Hansen concludes. “That’s just who he is.”

Tim Keller, the disciple

A key theme of the book is continuity. In 2014, Keller used the analogy which would give the book’s concluding chapter its title: learning is like adding “rings on a tree.”

“The gospel that saves sustains for our entire lives,” Hansen explains. “Jesus Christ is our everything. That’s the core. From there, through him and by him and for him, we learn; we add theology, Bible, history, sociology. We’re the same person, who is utterly dependent at the core on Jesus, but we continue to expand and grow through a lifelong process of learning.”

“Tim’s given us a model of how to age well and suffer well. I don’t think we should take that for granted.”

A month after Keller literally wrote the book On Death, he was diagnosed with pancreatic cancer. He has since commented, “My wife and I would never want to go back to the kind of prayer life and spiritual life we had before the cancer. Never.” He similarly told Hansen, “I’m not fighting my cancer; I’m fighting my sin.”

Hansen concludes, “Tim’s given us a model of how to age well and suffer well. I don’t think we should take that for granted.”

God only knows the depth of Keller’s legacy upon the church. Even Keller’s prodigious memory and Hansen’s comprehensive book can’t expose or predict every layer of his influence. But what cannot be missed is the centre: the gospel that saves has sustained Tim Keller for his entire life, and it will sustain him in the next.

Tim Keller passed away 19th May, 2023 (US). His final words were, “There is no downside for me leaving – not in the slightest.”