Even though he's stepping down as senior pastor, Tim Keller's ministry continues through a church planting movement in America's cities and around the world.
His Manhattan megachurch, Redeemer Presbyterian, has a 'City to City' network. In fact, Redeemer has started nearly 400 churches in more than 50 cities across the globe, according to the church's website.
Part of Keller's new role with Redeemer will be working with City to City, Christianity Today reported.
Redeemer's website describes City to City as "the missions arm of Redeemer."
"Redeemer City to City hopes to build a global movement of leaders and practitioners who build upon and adapt our 'DNA' to create new churches, new ventures and new expressions of the gospel of Jesus Christ for the common good," it continues.
"There's never been a more crucial time for this," Keller said in a video at RedeemerCitytoCity.com. "It's estimated that four million people a month are actually moving into the great global cities of the world."
"Which means every two months, that's eight million people, which is another Bangkok," he continued. "This is going to take more than just what I can do."
"This is going to take thousands and thousands of Christians around the world who are partnering with us in order to make this happen," Keller said in the video.
That same video cites God's concern for the biblical city of Nineveh in the text, Jonah 4:11, "Should I not be concerned about that great city?"
Keller explains that at the end of the book of Jonah, God is talking with the prophet:
"God makes a fascinating argument. He says to Jonah, 'Jonah, look at this great city of Nineveh. There's 120,000 people there who don't know their right hand from their left. Shouldn't I have compassion on them?'" Keller said.
"And he's saying to Jonah, 'Jonah, if you care about people, then you're going to care about cities because there's so many people there,'" Keller continued.
"That argument, which is a very emotional argument on God's part, resonates with me," he said.