They flew in from California and Oregon, from Virginia and Boston. They came with siblings and children; our old quartet’s cellist, Miriam, took her seat with 13 other family members.

They came because Mr. K. understood better than anyone the bond music creates among people who play it together. Behind his bluster  and behind his wicked sense of humor and taste for Black Russians  that was his lesson all along.

He certainly learned it the hard way. As a teenager during World War II, he endured two years in a German internment camp. His wife died after a long battle with multiple sclerosis. All those years while we whined that he was riding us too hard, he was raising his daughters and caring for his sick wife on his own. Then his younger daughter Stephanie, a violin teacher, was murdered. After she vanished in 1991, he spent seven years searching for her, never giving up hope until the day her remains were found.

Yet the legacy he had left behind was pure joy. You could see it in the faces of the audience when the curtain rose for the performance that afternoon. You could hear it as his older daughter Melanie, her husband and their violinist children performed as a family. You could feel it when the full orchestra, led by one of Mr. K.’s protégés, poured itself into Tchaikovsky and Bach. It powered us through the lost years, the lack of rehearsal time  less than two hours  and the stray notes from us rustier alums.

Afterward, Melanie took the stage to describe the proud father who waved like a maniac from a balcony in Carnegie Hall the first time she played there. At the end of his life, when he was too ill to talk, she would bring her violin to his bedside and play for hours, letting the melodies speak for them both. The bonds of music were as strong as ever.

In a way, this was Mr. K.’s most enduring lesson  and one he had been teaching us since we were children. Back when we were in high school, Mr. K. had arranged for Melanie and our quartet to play at the funeral of a classmate killed in a horrific car crash. The boy had doted on his little sister, a violinist. We were a reminder of how much he loved to listen to her play.

As the far-flung orchestra members arrived for Mr. K.’s final concert, suddenly we saw her, that little girl, now grown, a professional musician herself. She had never stopped thinking about her brother’s funeral, she told me, and when she heard about this concert, she flew from Denver in the hope that she might find the musicians who played in his honor. For 30 years, she had just wanted the chance to say, “Thank you.”

As did we all.