Volunteers prepared hot rolls and Iru Bru drinks for police officers and firefighters who were called to the landmark Mackintosh Building on Friday night.
Speaking with BBC News, Chief Officer of the Scottish Fire and Rescue Service Alasdair Hay praised the "warm-hearted" response of both the Salvation Army and emergency crews.
Several small sections of the site were still burning on Sunday evening. Firefighters were using thermal imaging to detect which areas were still alight.
The West Scotland Salvation Army's emergency response team member, Jon Scott told BBC Scotland on Saturday: "There's quite a lot of fire and police personnel on site, so there's been quite a demand and it's been quite hard to keep up with it but we're just about managing."
Responding to the interview, Scottish Nationalist Party MP for Glasgow Central, Alison Thewliss tweeted: "Absolute credit to the Salvation Army."
"I would like to echo the words of the First Minister - she and I both know what an outstanding job firefighters have done ... and what an outstanding job they always do."@Chief_SFRS visited the scene of #GSofA fire to thank crews and our emergency service partners. pic.twitter.com/V5g93NAlSD
— Scottish Fire and Rescue Service (@fire_scot) June 17, 2018
The cause of the fire - the second blaze to strike the site in four years - remains a mystery. The full condition of the building is not yet known.
The Mackintosh Building had been undergoing a multi-million-pound restoration project.
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