They stood up a bit slowly at first, hesitant to share their memories with almost 300 persons who crowded the pews, balcony and doorways of the National Memorial Church of God yesterday afternoon at a service for Walter C. Hardesty.

But before long, the Rev. Richard Harp was trying to choose among the friends, colleagues and relatives who simultaneously rose to speak, changing his plea from "come on, one more" to "okay, one more."

Hardesty, known to his friends as an unusually compassionate, witty and vibrant man of strong opinions, was killed last Thursday at the age of 46 while driving his cab through Northeast Washington, one day after he heard of a job he hoped would free him of cab driving forever.

To a professor at George Washington University, Hardesty was the clinical psychology student who brightened up a chronically dull afternoon class with his enthusiasm.

To a former student, he was the person "responsible for pushing me through high school and college."

To a colleague at Crownsville State Hospital, a psychiatric institution outside Annapolis, he was the quick-thinking intern who administered CPR to a stricken housekeeper.

To Connie Hambrick, a fellow parishioner, he was simply a man "who lived well . . . " Shaking her head for emphasis, she told the gathering, "God has to be pleased with that man."

A Sunday school teacher and father of two, Hardesty, who lived on Taylor Street, founded two Montessori schools in Washington before switching in midcareer to work toward a doctorate in clinical psychology. In both fields, he showed dedication, energy and stubborn determination that led one friend yesterday to marvel, "I don't know how he did it all."

Jogging at lunchtime, he would take along three of the most difficult patients at Crownsville State Hospital. He added the most troublesome patient to his intern caseload because "he thought he could improve her life" though "others had failed," said Gwendolyn Kirkland, his ward supervisor. He found time for the girl all the times she came to sit outside his office and "she improved greatly," said Kirkland.

Hardesty took to driving a cab in 1981 to bring in extra money while he studied psychology, though his wife Pat feared it was too dangerous. Combined with long days at the psychiatric hospital, his cab driving "exhausted" him and "he was ready to drop it" as soon as he found a job with enough pay, Linda Sapin, a fellow student, said.

After completing all the requirements for his degree except his dissertation this fall, he turned down a job suggested by Kirkland, his supervisor, telling her he would still have to drive a cab on that salary.

But he was hopeful about getting a job for $2,600 a year more with the Anne Arundel County schools, and he had received news of an opening on the day before he died, Hardesty's brother-in-law, Tom Plaut, said.

Police have no suspects in the slaying, according to Plaut. He voiced hope someone will call the police with a clue.