Ellen Bernstein, a river guide turned rabbi who blazed a spiritual trail in the environmental movement by undergirding it with the Hebrew Bible’s veneration of nature, died on Feb. 27 in Philadelphia. She was 70.

Her husband, Steven J. Tenenbaum, said the cause of her death, in a hospital, was colon cancer.

In 1988, when she was 34, Rabbi Bernstein founded Shomrei Adamah — the name is Hebrew for Keepers of the Earth — which she described as the first national Jewish environmental organization.

“The Creation story, Jewish law, the cycle of holidays, prayers, mitzvot (good deeds) and neighborly relations all reflect a reverence for land and a viable practice of stewardship,” Rabbi Bernstein wrote in “Ecology & the Jewish Spirit: Where Nature & the Sacred Meet” (2000).

She developed curriculums for students and teachers, organized conferences, and wrote scholarly articles and books to spread a gospel that resonated in progressive congregations and on college campuses. Her work gave a new dimension to the words “holy land” and to the synergy between heaven and earth.

“The first step toward ecological repair,” Rabbi Bernstein wrote in “Toward a Holy Ecology: Reading the Song of Songs in the Age of Climate Crisis” (2024), “is to love and identify with the natural world.”

With help from her friend Shira Dicker, she wrote “The Promise of the Land” (2020), an ecological version of the Haggadah, the text recited on Passover, to remind Seder participants that Passover — like the other harvest celebrations Shavuot and Sukkot — had links to nature.

In her writing, including another book, “The Splendor of Creation: A Biblical Ecology” (2005), Rabbi Bernstein invoked God’s creation of the Garden of Eden and his vision of the promised land as evidence of biblical environmentalism.

“Through her work with Shomrei Adamah, she illuminated and made accessible the ecological roots of Jewish tradition and developed a foundation in Jewish ecological thought and practice,” Mary Evelyn Tucker, a director of the Yale University Forum on Religion and Ecology, said in an email.

Ruth W. Messinger, the longtime New York Democratic politician who is now global ambassador for the American Jewish World Service, said in an email that Rabbi Bernstein had used her writings “to push the Jewish community to think about our obligation to protect the planet and invest for future generations.”

And Rabbi Arthur R. Waskow, a theology teacher and leader of the progressive Jewish Renewal movement, said by phone: “It is clear if you read the Hebrew Bible that whoever lives on the land is responsible for taking care if it. What she accomplished was making clear to people what their own love of earth was, and how to express it.”

Ellen Sue Bernstein was born on July 22, 1953, in Newburyport, Mass., about 45 miles north of Boston, the granddaughter of shoe manufacturers who had built a factory there. She was raised in Haverhill, Mass., about 15 miles to the west, on the New Hampshire border. Her mother, Etta (Feigenbaum) Bernstein, managed the household. Her father, Fred, was a leather salesman.

“During the summers,” Rabbi Bernstein wrote on her website, “I despaired that the adult world was flattening landscapes for housing developments, polluting the atmosphere in an effort to develop more and more commodities for our consumption, and ruining our waterways.”

Inspired by a high school ecology course, she enrolled in a pioneering environmental science program at the University of California, Berkeley. She led summer wilderness trips as a river guide in Northern California and taught high school biology. But by her mid-20s she had begun seeking a vehicle that could couple her spiritual passion, ignited at the Aquarian Minyan, a Jewish Renewal congregation in Berkeley, and her ecological agenda.

She received a teaching credential in life sciences from San Francisco State University, a master’s in biology from Southern Oregon State University and a master’s in Jewish education from Hebrew College in Newton, Mass. She was ordained as a rabbi in 2012 by the Academy for Jewish Religion in Yonkers, N.Y.

Rabbi Bernstein married Mr. Tenenbaum, a clinical social worker and psychotherapist, in 2005, and the couple moved to Amherst, Mass., where she became a spiritual adviser at Hampshire College. In 2020, she and her husband moved to the Mount Airy neighborhood of Philadelphia.

In addition to Mr. Tenenbaum, she is survived by her brother, Larry Bernstein, and her stepchildren, Tatyana and Ezra Tenenbaum.

In writing about the Song of Songs in “Toward a Holy Ecology,” Rabbi Bernstein said that while it is typically interpreted as an allegory about the relationship between God and the Israelites, she was struck by its lush description of the garden where the lovers meet.

“Though the Judaism of my childhood had never spoken to me, these words from the Bible opened my heart,” she wrote of these passages:

Get up! My beloved, my beauty.
Come away!
For now the winter is past,
the rain is over and gone.
The scarlet blossoms are shimmering in the land,
the time of the songbird has come
the voice of the turtle is heard in our land.
The new figs have appeared,
the grape blossoms give off their sweet smell.
Get up! my beloved, my beauty; Come away!

“Reading the Song, I could feel the spring well up in my blood; I longed to get up and run away with her,” Rabbi Bernstein wrote. “Whatever divinity I knew seemed to be bound up in this bodily experience of spring — of color, smell and sound — of this torrent of energy and this romance with the earth. That the Song could articulate something I didn’t have language for — that words from my own tradition could be meaningful — comforted and delighted me.”

“You have to nourish people,” she told the Jewish Women’s Archive in 2020. “And that comes from showing them the beauty in the world and the beauty in nature, from nurturing a love for the world, and from nurturing inspiration, possibility and creativity. This is critical to keeping people engaged and motivated. Finding beauty has been central in all my work.”