Gregory Porter performs at the Howard Theatre. (Kyle Gustafson/For The Washington Post)

Just before Gregory Porter took the stage at Howard Theatre on Wednesday, surprise guest Will Downing shared some words about the singer. “I was in my home in New York, and I heard this voice, and I couldn’t figure out who it was,” the R&B singer recalled. Then a friend played him one of Porter’s songs. “I said, ‘That’s him! That’s the dude!’ It changed my life.”

That’s how you discover Porter’s music: A friend tells a friend, who tells someone else. Then that person tells you to spread the word. There’s something magnetic about the singer, whose recent album “Liquid Spirit” provides a captivating spin on traditional jazz and Southern soul. Porter doesn’t need histrionics to grab your attention. He’s simply a big guy with a big voice. His rich baritone is always moving and assured, whether he’s discussing the beauty of daily struggles or the pain of lost love.

Not surprisingly, Porter’s show took on a church-like atmosphere, with the spectators as eager participants. “Uh-oh, I just got a chill!” a woman shouted as Porter sang “Be Good (Lion’s Song),” a fascinating heartbreak tale from his 2012 album, “Be Good.” “Sing it, brother!” the woman exclaimed during “Hey Laura,” a buttery slow jam detailing a last-ditch effort to repair broken romance. In several instances, fans rose from their seats to applaud the Grammy-nominated vocalist, not saving a standing ovation for the end of the night. They sang along as Porter, clad in a two-toned suit, carefully peeled off each note. “Y’all ain’t got nothing to do?!” he asked, seemingly amazed that so many people came to see him. “I ain’t nobody!”

Porter livened the proceedings with the flashy “On My Way to Harlem” and its syrupy ode to Harlem Renaissance pioneers Duke Ellington and Langston Hughes. On “Liquid Spirit,” Porter clapped until his wardrobe malfunctioned. “My watch popped off my hand,” he said, looking at the busted timepiece. “I paid good money for this watch.” Porter truly opened up on “Work Song” and “Free.” The former, introduced by a fluid drum solo, describes a time of “breaking rocks on a chain gang.” On the latter, Porter salutes his parents for the sacrifices they made to raise him.

Porter told stories, made jokes, high-stepped and made direct eye contact with his fans. And when they wanted more, he obliged. Shortly after 9 p.m., Porter re-emerged for just one more tune, the reflective “Real Good Hands,” before finally taking off. Tell your friends what you saw. Tell them about that voice.

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Moore is a freelance writer.