Ronald J. Sider, an evangelical Christian author and speaker who, in an era when evangelicals increasingly aligned themselves with the political right, argued that Christ called the faithful to attend to social justice issues like racism and poverty, died July 27 at his home in Lansdale, Pennsylvania, near Philadelphia. He was 82.

His son Theodore Sider said the cause was cardiac arrest.

In 1973, Sider was among a group of religious leaders that, at a conference in Chicago, issued what became known as the Chicago Declaration of Evangelical Social Concern, “confessing our failure to confront injustice, racism and discrimination against women, and pledging to do better,” as he would summarize the document later.

The declaration, of which Sider was a principal architect, was bold for the time: It stated emphatically that the evangelical emphasis on personal salvation was not enough.

“We acknowledge that God requires justice,” it said. “But we have not proclaimed or demonstrated his justice to an unjust American society. Although the Lord calls us to defend the social and economic rights of the poor and oppressed, we have mostly remained silent.”

Sider pressed that case further in his book “Rich Christians in an Age of Hunger,” published in 1977. In it, he laid out what he saw as the biblical command to aid the poor, and he lit into evangelicals and other Christians who let themselves be seduced by advertising that hawked the benefits of affluence.

“People persist in the fruitless effort to quench their thirst for meaning and fulfillment with an ever-rising river of possessions,” he wrote. “The personal result is agonizing distress and undefined dissatisfaction. The social result is environmental pollution and neglected poor people.”

The book, which has been reissued frequently — with Sider updating it to account for AIDS, the fall of the Soviet Union and other world developments — has sold hundreds of thousands of copies. In 1978, its success encouraged Sider to start Evangelicals for Social Action (now Christians for Social Action), a group that has been a voice not only on poverty but also on nuclear disarmament, apartheid, the environment and other issues.

While many evangelicals were aligning with the politics of the right (the Rev. Jerry Falwell founded the Moral Majority the next year) and focusing on abortion and issues of sexual identity, Sider spoke and wrote from the left, remaining vocal and politically involved for half a century.

That included trying to counter the support among White evangelicals for Donald Trump. In 2020, he edited “The Spiritual Danger of Donald Trump: 30 Evangelical Christians on Justice, Truth, and Moral Integrity,” a book that, he told Sight magazine, “grew out of an obvious concern that White evangelicals were not thinking in an adequately biblical way in their reflections on Donald Trump, his character and his policies.”

Sider wasn’t without his conservative side, especially concerning same-sex marriage and abortion. And he cautioned against being overly focused on causes — one of his books was called “I Am Not a Social Activist: Making Jesus the Agenda” (2008). But he had hope that a faith of personal salvation and one of advocacy on social issues could coexist.

“I long for the day when every village, town and city has congregations of Christians so in love with Jesus Christ that they lead scores of people to accept him as personal Savior and Lord every year,” he wrote in “Good News and Good Works: A Theology for the Whole Gospel” (1999), “and so sensitive to the cry of the poor and oppressed that they work vigorously for justice, peace and freedom.”

Ronald James Sider was born Sept. 17, 1939, in Stevensville, Ontario. His father, James, was a farmer and later a pastor, and his mother, Ida (Cline) Sider, was a homemaker.

He grew up attending the Brethren Church of Christ. His interest in social activism started there.

“It was thoroughly evangelical but had not experienced the wrenching early-20th-century divisions of the social gospel-fundamentalist battles that helped produce the huge gulf between evangelism and social action,” he wrote in “Good News and Good Works.” “In my early years in the faith I just assumed that devout Christians shared the gospel, as my missionary uncle had in Africa, and also cared for the poor, as my church’s relief agency was doing.”

He earned a bachelor’s degree at Waterloo Lutheran University in 1962 and later in the decade earned a master’s degree and a Ph.D. in history at Yale University and a bachelor of divinity degree at Yale Divinity School. He was an ordained minister in both the Mennonite and Brethren of Christ denominations, but teaching was his main career.

In addition to his son Theodore, Sider is survived by his wife, Arbutus (Lichti) Sider, whom he married in 1961; another son, Michael Jay Sider-Rose; a daughter, Sonya Marie Smith; and seven grandchildren.

Sider’s book “I Am Not a Social Activist” includes a chapter titled “What Keeps You Going, Ron?”

“I hope that I have, by God’s grace, allowed Jesus’ resurrection to shape the way I live — it certainly has shaped the way I hope,” he wrote in that chapter. “I expect to see Jesus. I believe that he will make good on his promise to complete his victory over the devastation Satan has caused in God’s wonderful world.”