Garth Brooks played in Indianapolis, Ind., for the first time in 21 years on Thursday night (Oct. 5), and he came to the stage -- with heightened security measures in place at the venue -- sporting a "For Vegas" T-shirt in honor of the victims of the deadly Oct. 1 shooting rampage at the Route 91 Harvest Festival in Las Vegas, Nev. It was Brooks' first time onstage since the tragedy.

"People come here to forget. They come here to sing, to enjoy it," Brooks says, explaining the effect of such a tragedy on the country music community. "Extraordinary people acted, that were just ordinary people. In any tragedy, heroes arise, and that's what I would like to focus on."

Country Stars Respond Following Route 91 Harvest Festival Shooting

Previously, Brooks shared a video message on social media, encouraging his fellow artists to "start the music again." He is one of many artists who have been paying homage to the country music fans who killed and injured in the worst mass shooting in modern American history.

"The show must go on ... When things go bad, music and musicians go to work," Brooks says. He encourages his fellow artists, "Start spreading the love, start creating the greatest power that music holds, that's the power to heal. All things good should start with you. If you believe it, start it up."

All four nights of Brooks' World Tour stop in Indianapolis, with Trisha Yearwood, are sold out. Thursday night's show was the artist's first appearance of the run, which is taking place at Bankers Life Fieldhouse.

Remembering the Route 91 Harvest Festival Shooting Victims