Sometimes the simplest act of kindness can bring the greatest joy.

This past weekend in Revere, Massachusetts, some unidentified vandals spray-painted messages of hate on the B’Nai Israel synagogue. Bright red hateful words and symbols confronted the synagogue’s members the next day as they made their way to their service and a breakfast.

Marilyn Dorfman was horrified.

“It was really sickening,” she told Boston TV station WBZ-TV. “The information on the kitchen door also was very reminiscent of things that you saw in concentration camps in Nazi Germany.”

She and other members tried to push away the pain as they went inside for their service.

When they came out afterwards, an unidentified man was just finishing up painting over the offensive markings. No one had called him. He had just shown up with paint that was amazingly close to the beige color of the walls— and went to work.

Ira Dorfman says he tried to get the man’s name. “He wouldn’t tell me. I said ‘May I take your picture?’ And he said, ‘You can’t.'”

The man finished the job, packed up his supplies, and drove away.

Members say the gesture was so moving, it made up for the hateful words they had seen on their way in that morning.

Still no word on the identity of the mysterious stranger.