here was a time when Elizabeth Chavis was confident of the inevitability of an acquittal for her son, The Rev. Benjamin Chavis, and his nine co-defendants - the Wilmington 10.

She has changed.

"I really didn't believe a thing like this could happen, that it could drag on so long. I didn't believe 10 young people could be framed," the 62-year-old woman said last week.

"Has your spirit ever been so full you can't take any more?" she asked.

"That's how I felt when they took them back to prison. I became indignant."

Once satisfied to remain in the background, Elizabeth Chavis now campaigns publicity for the 10 defendents - nine black men and one white woman - convicted and sentenced on charges arising from a week of racial strife in Wilmington, N.C. in 1971.

Today she will join a march for the Wilmington 10 from Malcolm X Park to the Ellipse.

Joining the fundraisers and rallies has done two things for her, according to friends. Her participation, said a minister, helps her believe "she is Ben on the outside of prison.

"Sometimes I know she doesn't feel like going. But last Sunday we drove 2 1/2 hours to Fayetteville and afterward, her face looked stronger, she was livelier," said Richard Harris, friend and neighbor who travels with her.

Last month she marched outside the White House and last July addressed 3,000 people at a rally at Lafayette Park. sponsored by the United Church of Christ. Her voice trembled that day, as she reminded Jimmy Carter of the confidence blacks had had in him. "It's really in his hands now. I never want a case like the Wilmington 10 to happen again."

The 10 young people now known as the Wilmington 10 were arrested in March, 1972 on charges of conspiracy and arson in Wilmington grocery stone firebombing. Ben Chavis, in fact, had been dispatched to Wilmington on behalf of the United Church of Christ, in which he was a minister.

In one of the most controversial racial cases in his country in years, the convictions were appealed and appealed again as supporters charged literally thousands of judicial errors, unfair and partial jurors, witholding of evidence and perjured witnesses.

After appeals proved fruitless, supporters of the group - who had raised hundreds of thousands of dollars for legal fees - turned their efforts toward seeking a pardon. Gov. James B. Hunt of North Carolina, in a compromise that pleased no one and drew harsh criticism from all sides, reduced some of the sentences, but withheld an actual pardon. (One of the 10, Anne Shepard, has been paroled.)

Over the course of the appeal process, publicity about the case brought support from political, civil rights and church groups all over the country. Amnesty International regards it as the major prisoners.

As it happened, the day before the pardon was denied last January, a group of Ben Chavis' friends went to the prison in McCain, N.C. to help him celebrate his 31st birthday.Elizabeth Chavis was obviously keyed up, pensive, and kept walking around, looking up at the sky.

"She had heard that something was going to happen," said a friend, "but somehow she felt it wasn't going to be good for Ben."

"I had been quite lonely," says Elizabeth Chavis. "Ben is my only son. Two of my daughters live in Charlotte, that's 197 miles away from Oxford, and the other daughter lives in Germany." Chavis is a tall, broad woman with a bounce of auburn curls. Her voice has the slow, measured pace of a woman who stood, as she did, in a classroom for 30 years.

"I sat through all those court sessions and I tried not to let it get me down," she says. "I prayed, it takes prayer in a case like this. But, finally I realized that there was much work to be done on the outside. And Ben agreed it was necessary. He always said 'Be careful."

Elizabeth Chavis grew up in Oxford, N.C.; her family was faithful to the code of hard work, law-obedience and church attendance. "In Oxford the people have remained quiet about the case. I don't know why but they know no member of my family has ever given the law trouble," says Chavis. She walked two miles to segregated schools, had apple cores thrown at her from the window of the passing white children's school bus, and was called, she says, "uncomplimentary names." Chavis and her husband, also a school teacher and an elder in the church, raised their four children on gentle protest, a philosophy that was called nonviolence.

The direct incentive for her son's activism, she recalls, was a beating by three whites. "It was the first year the high school had been integrated. The bill had been legislated but the minds hadn't. Ben was beaten up during the recess in a basketball game. He fought back, he kicked them in the face."

Elizabeth Chavis' personal ordeal has been relieved, she says, by her son's strength - "He's growing more devout" - and the comfort of the case's supporters. Recently she received a telegram from 123 women's organizations in Europe. "They let me know I was not alone." On the Sundays she is in North Carolina she visits her son in jail, 260 miles from Oxford. Usually, they talk about her health and safety and Chavis' three children.

"Ben's oldest child, Natalie, said recently 'I didn't know Daddy would be gone so long.' And I never miss the oppurtunity to tell her he's in prison unjustly," says Chavis. "I try to submerge the bitterness - and that's hard - because you want to repay. I can't let go of that hope. And I can't say I have the faith, if I don't have that hope."