The shooting as of Monday afternoon had claimed the lives of 58 people and injured more than 500.
But he said even though people may feel that way, we still need to push for peace over violence.
The Australian country singer then covered Simon and Garfunkel's "Bridge Over Troubled Water", and was followed by Alison Krauss and The Cox family who led the vigil in prayer before singing "Amazing Grace".
"This is the kind of city that will wrap its arms around you, and that is exactly what we're here to do tonight", the evening's master of ceremonies, actor Charles Esten said as he began. "As long as there is somebody that might have a voice for those that have been stilled... we gotta fight the fight", Gill told PEOPLE.
People gathered at the Nitro Church of God to stand in solidarity with those impacted by the mass shooting at a country music festival in Las Vegas.
"We're here to lift up those who died".
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He was found liable for the killings in a civil court hearing two years later and ordered to pay the victims' families $33.5m. On Oct. 3, 1995, at the end of a televised trial that captivated the nation, Simpson was acquitted of all criminal charges.
Barry organized the vigil along with CMA and Nashville Convention & Visitors Corp.
Keith Urban followed the mayor, saying he first wanted to offer his prayers and love to everyone affected by "last night's horrific tragedy".
"I started this morning finding out about it and being shell-shocked". He can be seen running from stage as he, and the thousands in the crowd, realized what was happening.
The memorial will take place on Monday, October 2 at 6pm in downtown Nashville and will be put on by the city of Nashville and the Country Music Association.
Las Vegas Metro PD has set up a hotline to assist with anyone searching for missing family and friends.