Like a lunar event or a geyser, it came at the expected hour: 5:45 on a late-August Saturday afternoon at the Charlie Parker Jazz Festival in Marcus Garvey Park in Harlem. (My notes from last year mark it at 5:30.) It’s not planned, it just happens: the tempo shifts down and it becomes time for a few dozen audience members — mostly retirement age, probably sharper looking than you — to go down in front of the stage and dance together, full of grace. It’s something you ought to see.

The cue was Cécile McLorin Salvant’s singing the standard “You’re Getting to Be a Habit With Me,” and if the swing in it was amazing, easy and deep, this version was spacious, inviting bodies to occupy it. Ms. Salvant, who is 23 and whose career is just taking shape, put some kind of spin on every word, playing with sound and words.

She’d earned the audience’s trust, admiration and humor, as well as its silence. She connects with jazz’s past and prehistory while being entirely about risk and play in the present, making her voice go precise or foggy, deviating from pitch or hyper-elongating a syllable. It’s fantastic to see a young musician with this much intelligent control over her material and her audience.