“We must learn to live together as brothers or perish together as fools,” said Martin Luther King Jr., assassinated in 1968. The cool jazz great Dave Brubeck responded with The Gates of Justice, juxtaposing King’s words with texts from Hebrew liturgy and the Bible. Completed in 1969, as the Civil Rights era was ending, the 50-minute cantata meant to forge unity between America’s Black and Jewish communities. “When King said, ‘We must live together as brothers,’ people didn’t hear it,” Brubeck declared. “Now they damn well hear it.” But the piece, as much as the ideals it enshrines, has been sorely neglected. The conference Music and Justice aims to remedy what it can. Brubeck’s sons Chris, Dan, and Darius are on hand as the jazz trio for their father’s centerpiece. The musical offerings also include several premieres. —Matthew Gurewitsch