The Dakota Access Pipeline isn’t just about the environment. It’s about religion.

Activists fighting to stop the Dakota Access Pipeline in North Dakota welcomed new developments after the Army said Sunday that it will not approve an easement. Protesters saw the announcement as a key victory for Native American tribes and others who have flocked in recent months to protest the oil pipeline, which tribal leaders say threatens lands and artifacts they consider to be sacred.

Energy Transfer Partners, the pipeline’s developer, says it will create thousands of construction jobs and millions in tax revenue, and Donald Trump has vowed to support pipelines like this one. To the pipeline’s opponents, however, the pipeline runs within a half-mile of the Standing Rock Sioux Reservation, and the tribe’s leaders argue that it threatens the drinking water for local Native Americans.

The latest wave of activism surrounding the pipeline has brought a diverse range of groups together, including representatives from religious communities such as the United Methodist Church and the Nation of Islam, who have visited the camps or spoken out against the pipeline project. Many activists have framed the issue as an environmental issue, but some observers highlight the importance of Native Americans and how they understand their religion and the land.

Religion to many Native tribes is very land-based, said Stephen Pevar, an attorney for the ACLU who has specialized in Indian and tribal rights cases. Many Americans move several times throughout their lifetimes, making it difficult for some to understand how crucial land is to Native spirituality, he said. Native Americans have a bond to the land and nearly every tribe has its own sacred lands.

“To the Indians, this is both water and it’s religion, whereas many white people seem to be pretty dismissive about the religious aspect and view it as more environmental,” Pevar said.

Imagine, he said, if the pipeline was being built in Bethlehem, underneath Jerusalem or a similar holy site. “That’s how this is viewed by the people there,” Pevar said. “White people, unfortunately, don’t share those views. They don’t realize the religious significance of these locations.”

Protesters contend that the pipeline violates the National Historic Preservation Act, which requires agencies to “consult with any Indian tribe … that attaches religious and cultural significance to properties with the area of potential effects.”

Native groups also rely on the American Indian Religious Freedom Act of 1978, which requires the federal government to “protect and preserve for American Indians their inherent right of freedom to believe, express, and exercise [their] traditional religions … including but not limited to access to sites, use and possession of sacred objects, and the freedom to worship through ceremonials and traditional rites.”

Some people can fall into the trap of overgeneralizing American Indian spirituality, according to UCLA professor Peter Nabokov, who maps different beliefs about “sacred places” in his book “Where the Lightning Strikes.”

The North Dakota pipeline project has drawn a large number of environmental activists toward the Native American cause, Nabokov noted. “It’s in position to galvanize a range of support from a variety of interests, many of whom don’t know that much about American Indian spirituality and religion, but maybe this is a way they’ll start to learn,” he said.

Papers filed in federal court in September note why Native Americans believe sites on the private land are significant, according to Tim Mentz Sr., the tribe’s former longtime historic preservation officer. Mentz wrote that one stone feature representing an area used for prayers and spiritual journeys with a grave extends into the pipeline corridor and would be destroyed.

Mentz also wrote that the area around the Cannon Ball River drainage near the Missouri River held significance as a gathering area for tribes. “Numerous sacred sites were located there and were known by the tribes as a very holy place or ‘wakan’ and no warfare or spilling of blood occurred there,” he wrote. “Warring bands or enemies never created conflict with each other as a spiritual presence was there and all who came knew and felt it. All came to pray at this site having no fear of war or bloodshed.”

Belief that a site is sacred rarely translates into federal protection of Native American places for their religious significance, writes Rosalyn R. LaPier, a visiting assistant professor at Harvard Divinity School. And to understand the pipeline debate, she argues, you must understand what makes a site sacred.

“My grandparents said that sacred areas are places set aside from human presence,” LaPier wrote. “They identified two overarching types of sacred place: those set aside for the divine, such as a dwelling place, and those set aside for human remembrance, such as a burial or battle site.”

Rituals and spirituality have also been central in the North Dakota pipeline demonstrations, Jack Jenkins wrote for ThinkProgress. Each tribe has its own unique set of practices, but spirituality has been a “core mobilizing and stabilizing force for the movement.”

Greg Johnson, a Hawaiian religion expert and an associate professor of Religious Studies at the University of Colorado, Boulder, said the indigenous protests are increasingly led by organizers who are “generating” religion through their activism. “The kids of today’s generation know a new set of chants, a new set of prayers because of those who came before them,” Johnson told ThinkProgress.

Prayer has been very visible during the demonstrations. The movement started April 1 with a nearly 30-mile prayer ride on horseback, Emily Miller wrote for Religion News Service. “That prayer has continued in the camps since then: communal prayers in the morning and evening and at mealtimes; prayers in vigils and in songs; prayers while sage, cedar and tobacco are burned,” she wrote. “And the Standing Rock Sioux have invited all people to join.”

The demonstrations have attracted attention from mostly mainline Protestant denominations, though some see Pope Francis, who has written an encyclical on the environment and spirituality, as a natural ally. Representatives from the Presbyterian Church (USA), United Church of Christ and the Episcopal Church have visited the Standing Rock camp or expressed solidarity with the protesters, according to Religion News Service. On Nov. 3, more than 500 clergy led prayers and sang hymns while marching to a bridge that has been the site of clashes between demonstrators and police.