Seven decades of harmony, history, and hits. And the Gatlin Brothers are bringing all of it to the Franklin Theatre for Christmas. Grammy-winning Larry, Steve, and Rudy Gatlin, the Grand Ole Opry legends behind “All the Gold in California,” “Houston,” and “Broken Lady,” take the stage for a holiday night that blends their greatest hits with beloved Christmas classics. This is the kind of holiday tradition that reminds you why some voices never go out of style.