Last Tuesday, Democratic debate moderators asked the candidates about their life mottos. Bernie Sanders offered a quote from Mandela. Joe Biden spouted his trademark folksy wisdom. But Elizabeth Warren seemed most prepared, quoting the words of Jesus from Matthew 25:40, “in as much as ye have done it unto one of the least of my brethren, ye have done it unto me.” And yes, she went with the King James Version. The ultimate flex.

It’s not the first time Warren, a Methodist, has referenced the verse as a motto. She quoted it at the DNC all the way back in 2012, when she was relatively new to the national arena. But even before that, the verse had become a cornerstone for people of faith on the left. In a country where Christian politics is popularly considered Republican territory, Democrats have rallied to Matthew 25 as a way to prove that their legislative agenda has scriptural backing too.

Warren’s not alone. Early in Pete Buttigieg’s now-defunct presidential campaign, he implicitly dinged President Donald Trump in a televised commercial, saying “In our White House, you won’t have to shake your head and ask yourself: whatever happened to ‘I was hungry and you fed me. I was a stranger and you welcomed me.'”

Sanders is not religious and did not quote Matthew 25 during his 2015 speech at Liberty University, but his appeal to the largely evangelical student body was that he and they could find common ground in caring about how the poor are treated. “When we talk about justice, we have to, in my view, understand that there is no justice when so few have so much and so many have so little,” he said.

And then Representative Alexandria Ocasio-Cortez certainly seemed to allude to the verse as well during a congressional hearing about LGBT communities, referencing marginalized communities as “the least of these.”

“I feel as though if Christ himself walked through these doors and said what he said thousands of years ago: that we should love our neighbor and our enemy, that we should welcome the stranger, fight for the least of these …he would be maligned as a radical and rejected from these doors.”

It’s not a new phenomenon, nor is it a coincidence. In fact, Matthew 25 has been a rallying point for Christians on the left since the early days of President Barack Obama’s presidential campaign, when his supporters started looking for ways to make an organized appeal to Christian voters.

In 2008, a strategist named Mara Vanderslice (now Vanderslice Kelly) started a grassroots PAC for Obama’s Christian supporters called the Matthew 25 Network. Their thinking was that the Religious Right dwarves the Religious Left in terms of both financial resources and sheer numbers. The Matthew 25 Network was a way to push back.

“I think it’s interesting because the text is so extreme, in a way,” says Guthrie Graves-Fitzsimmons, fellow at The Faith and Progressive Policy Initiative at the Center for American Progress. “It shows that Democrats are willing to not just talk about faith and their Christian beliefs in a general way but in an ‘if you don’t agree with us you’re going to hell’ way.”

Graves-Fitzsimmons is right. In Matthew 25, Jesus tells His followers that the Son of Man will return to earth to divvy up all humanity — the righteous to His right and the unrighteous to His left.

“Then the King will say to those on his right, ‘Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world,” Jesus says. “For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me.’”

The righteous are confused and tell the King they don’t remember doing any of this for Him. “The King will reply, ‘Truly I tell you, whatever you did for one of the least of these brothers and sisters of mine, you did for me.'”

The unrighteous hear the unfortunate inverse of the same message: every time they refused kindness and generosity to society’s lowly and outcast, they were really refusing it to God. “Then they will go away to eternal punishment,” Jesus says. “But the righteous to eternal life.”

For Christians on the left who seek to manifest their faith in their politics, the policy implications here are stark. Investments in the social safety net, generosity along the border and gentleness in foreign policy aren’t just prudent politics, they’re treating the “least of these” as if they were Jesus Himself.

Of course, not everyone sees it that way. In 2018, Liberty University President Jerry Falwell Jr. responded to Tom Arnold’s invocation to read Matthew 25:40 (reader, Twitter is strange) by saying he believes the verse means we should lower taxes.

Falwell’s interpretation here is not exactly mainstream. A more charitable conservative read comes from New Testament scholar Craig Blomberg who, as noted by Justin Taylor at The Gospel Coalition, suggests that the “least of these” was referring to missionaries. However, Alyce M. McKenzie, Le Van Professor of Preaching and Worship at the Perkins School of Theology disputes this interpretation, writing that “the presence of Jesus is hidden in the sick, the hungry, the thirsty, the naked, and the imprisoned … blessedness comes from active compassion toward those that society and, in some cases, religion, have judged as accursed.”

The latter is the interpretation that has become popular among progressive Christians, largely through the advocacy of Sojourners founder Jim Wallis, who cites Matthew 25 as his “conversion text.” Reverend William J. Barber also frequently references Matthew 25 in his sermons and online. Guthrie-Graves says that for those who believe in progressive policy goals like expanded healthcare or immigration reform, Matthew 25 is an encouragement to put their faith into action in a large, organized way that would maximize its impact at a national or even global level.

“The government is the people coming together to enact our values for how we want to live together and provide for the common good,” he says. “Christians throughout American history and a much broader history have advocated for government policies to reflect their values as Christians.”

When Democratic politicians discuss their religious views, it is to a largely receptive audience. According to Pew Research, 76 percent of Democrats are “fairly” or “absolutely” certain that God exists, and 70 percent say religion plays an important role in their lives. That’s lower than the numbers for Republicans (90 and 80 percent, respectively) but it’s still a majority. Despite the public impression to the contrary, Democrats value their faith and value their politics. One study even found that despite its smaller size, the Christian Left is “the most active group in American politics.”

Michael Wear, founder of Public Square Strategies and former Obama staffer, agrees that progressives find Matthew 25:40 appealing because it “seems like and reads like a very practical verse — it’s very much about faith and action.”

Wear acknowledges the conservative critique that the government can not be enlisted into putting every command of Jesus into action, but he says biblical teaching still has implications for American voters.

“Sure, the verse itself is not about the state. Sure, the verse specifically is talking about you as an individual,” Wear says. “But we happen to live in a country where each individual has responsibilities that are personal and also political. Each of us holds a political office. The question is, how do you steward that political office in a way that’s consistent with the heart and teachings of Scripture”

Wear also urges voters to be cautious about reading too much into candidates from either party who invoke the Bible. “If voters can be appeased through a few scripture citations then politicians will do that,” Wear says. “That’s easy for them. It’s meaningful that they’re speaking this way. But it’s not meaningful because it gives us the feels. It may be meaningful because they can be held accountable to policies that will uphold the kind of values that they’re using that verse to push forward.”

As Democrats attempt to mount a real challenge to President Donald Trump in November, faith will doubtless take a center stage as it has in almost every presidential election in American history. Trump’s white evangelical base has shown few signs of wavering in their support. It may be that, for better or worse, white Protestant Christianity simply has a rightward tilt in the U.S. But to the extent the Religious Left is interested in mounting a challenge, Matthew 25 is its rallying cry.