They were not close in the beginning. One educator taught Spanish, the other art, each consumed by the whirlwind of busy days in the classroom. But in the spring of 2016, Sunny Grissett read a Facebook page created by Vivian Rivera-DeLeon.

She needed a kidney.

What has unfolded since has helped save a life and inspire a wider community, as one teacher’s need became another’s cause, forging a bond so strong the women have come to think of themselves as sisters.

“Both of them have the biggest hearts,” said Sarah Bannat, a fellow educator at John Hanson Montessori School in Oxon Hill, the Maryland public school where the women teach. “Every time I start talking about them, I start to cry.”

The story of Rivera-DeLeon’s transplant — and Grissett’s gift — is at once increasingly common and not common enough. Patients are regularly added to a lengthy national transplant waiting list, and many die before ever receiving a donated organ.

Those lucky enough to find a living donor often are helped by a relative or spouse. But in the last two decades, there has been a sharp rise in kidney donations from acquaintances — co-workers, neighbors, fellow church members, friends.

In the Washington area, a police officer in Charles County last year received a kidney from a fellow officer he had known since childhood. In the celebrity world, pop star Selena Gomez’s close friend gave her a kidney. In a Florida school, a teacher donated to the mother of one of her fourth-graders.

For the Maryland teachers, the big day came Jan. 25 at Johns Hopkins Hospital in Baltimore — a time they had anticipated for much of a year. That morning, hours before being wheeled into an operating room, Rivera-DeLeon posted a photo of herself and Grissett on Facebook.

“The Miracle!!” she wrote.

Jacquelyn “Sunny” Grissett, 31, became the full-time art teacher three years ago at John Hanson Montessori, a close-knit school with a little under 500 students from pre-K to eighth grade. She and Rivera-DeLeon, 40, were casual friends.

But last March, Grissett invited the Spanish teacher and another educator to an annual hope night at her church, LaPlata Baptist. The evening sparked plans among the three for a weekly Bible study, and they later gathered at Grissett’s home.

Grissett had not seriously considered being a donor, and the issue did not come up that night, she said. But after the teachers left, she said she was overcome.

“I was sitting in my living room. All of a sudden I felt like full, like every edge of me was pressed. and I can only express it as it was the Holy Spirit and I had a complete undeniable understanding that I was going to give my kidney to Vivian,” she said.

Her husband, Mike, who owns a barbershop, walked through the door afterward, she said, and she expected a shocked reaction. Instead, he told her he had just watched a television program about live-donor kidney donations as he swept up his shop. He had nearly called for more information, she said.

“God prepared him to hear what I had to say,” she said.

Despite feeling called to donate, Grissett admits she struggled at first. She thought of pain. She thought of dying. She cried as she commuted to work. But after maybe 1o days, she said, she stopped thinking of her own risks.

She thought of Rivera-DeLeon.

Rivera-DeLeon started at John Hanson in 2008 — an educator who grew up in Puerto Rico and who connected easily with children and loved teaching. Though she could be reserved, she was bubbly among friends, a woman who found humor in life and was deeply proud of her two sons and daughter.

In 2010, Rivera-DeLeon said, she was diagnosed with Lupus, and kidney problems soon followed. She received treatment and dialysis. She did not dwell on her health problems at school, colleagues said. In recent years, she was an assistant coach for the school’s baseball and basketball teams.

“It took me by surprise that she was even sick,” said Antje Hultgren, who teaches PE at the school and has become a friend. “She comes into work with a smile. She doesn’t complain.”

In April, Grissett recalls, she and Rivera-DeLeon were standing near the school entrance, waiting for children to arrive. Grissett had not yet mentioned donating the kidney, thinking she should get blood tests first. But that morning, Rivera-DeLeon seemed uncharacteristically down.

So she told her.

Rivera-DeLeon’s reaction: No.

She knew Grissett and her husband were trying to start a family. She said she did not want Grissett to do anything that might interfere.

“I’m not going to let you,” she told Grissett. “You want kids.”

Grissett insisted.

“You have three kids,” she told her. “And they need their mom.”

There has been a dramatic rise in live kidney donations from nonfamily members, which last year accounted for about 35 percent of the total, up from 5 percent in 1995, said Dorry Segev, a transplant surgeon at Johns Hopkins University.

The increase was initially driven by the development of minimally invasive surgery to remove donor kidneys, he said, but the trend continued amid cultural changes that inspired people to donate.

“Getting a kidney transplant from a live donor doubles your remaining life expectancy,” Segev said. “That’s huge.”

Segev emphasized that donors no longer have to be a biological match. Doctors find ways around incompatibility through a medical procedure called desensitization, which shifts a patient’s immune system in a way that protects a transplanted organ, or through a swap between patients with live donors so that each gets a suitable kidney, he said.

The Maryland teachers, as it turned out, shared the same types of blood and tissue.

They discovered plenty of other similarities: Both are 5-foot-2 and wear the same shoe size and like the same clothes and jewelry. Not only do they teach at the same school, both live in Waldorf, about 35 to 45 minutes south of where they work.

They began to spend time together outside of work and learn about each other’s lives.

Grissett, whom one friend described as hilarious and wise beyond her years, met her husband at a Bible study when she was 20 and married a year later. Teaching art is a passion. She puts together an annual art show at John Hanson, a fancy affair with a red carpet and formal attire, to showcase student art work. She studied — and enjoys — the language Rivera-DeLeon teaches.

Last year, the Grissetts also grew close to Rivera-DeLeon’s children — ages 18, 16 and 13.

“I cook for her, and she does my hair,” Rivera-DeLeon said one day before the transplant. “It’s a good trade.”

But there were bumps on the road that led to the transplant, both women recall. Grissett said she was told in July by a doctor at another hospital that she could not donate because her protein levels were too high. She asked for a retest, which she said confirmed the problem. She was told to seek medical care for herself, she said.

“I’ve never been so low in my life,” she said.

She said she prayed. Rivera-DeLeon prayed. Their friends and relatives and churches prayed. And she said a few months later, a Hopkins doctor reached a different conclusion: Her protein levels were excellent — and her kidneys were beautiful.

“I knew that was from God,” she said, describing the seeming setback as “an opportunity to practice my faith in Christ.”

It was late November when Grissett’s cellphone rang during a break at school. When the call ended, she ran to Rivera-DeLeon’s classroom.

“I’m our donor!” she exclaimed.

Rivera-DeLeon put both her hands over her mouth.

By the time the surgery date arrived in January, the news about Grissett’s gift to Rivera-DeLeon had swept across John Hanson. Teachers were emotional. Parents were awed. Students were impressed and full of questions.

“Seriously, don’t you need that kidney?” one quizzed Grissett, who assured children that she had two kidneys and would be fine with one.

Zory Kenon III, the school’s principal, called the gift “a phenomenal act of kindness.”

“It’s the most courageous thing I’ve ever experienced in my educational career,” he said.

Inspired by the generosity, the PTSA threw a fundraiser to help support any uncovered medical or living expenses the women might incur.

“They have done so much for our community, and it was a way to tell them we care about them and we are praying for a speedy recovery,” said Nicole Nelson, the PTSA president.

Segev, the Hopkins doctor, called the surgery “textbook” — successful for patient and donor. More than 98 percent of live-donor kidney transplants are still functioning after a year, he said.

“It’s been awesome to see two co-workers become sisters because of a crisis, and then that brings the whole community together,” said Tia Breckenridge, the school’s counselor.

A day after the operation, the two teachers posted selfies in their hospital gowns.

Rivera-DeLeon wrote:

“My twin!!! Sunny Grissett

God put us together!! No doubt about it...❤❤❤❤”

The recovery has had ups and downs, particularly for Rivera-DeLeon. But she said she is grateful to many people, and especially to Grissett. Both teachers hope to be back in their classrooms in coming weeks.

Grissett has an art show to put together.

Rivera-DeLeon wants be back in her Spanish classroom — and on the playing field, too. Come spring, she will be the coach of the school’s soccer team.