The HeraldGeorge McNeilage, a friend of the family, also paid tribute to the teenager during the 50-minute service. Mr McNeilage, secretary of North Pollok community council and an activist with the Scottish Socialist party, revealed that he had tried to talk Fusilier Gentle out of enlisting.
He described the young man as an "economic conscript", but said the teenager had been determined to carve out a career in the forces.
Mr McNeilage recalled: "He told them he wanted to make something out of his life and not be like other teenagers in the schemes who hang around the street corners with nothing to do."
Mr McNeilage added: "He was an economic conscript. He was literally signed up when he went to sign on the buroo. His words to me were: 'Big man, I am only getting a bit of work here and there. At least I'll get my driving licence, I'll get to see parts of the world I wouldn't get to see, I'll get a permanent wage and I might get a trade out of it.'"
Tommy Sheridan, the SSP MSP, also paid his respects.
Neil Mitchell, 63, from Pollok, was one of hundreds of people who listened to the service, relayed outside through loudspeaker.
With tears in his eyes, he said: "My two sons went into the army because there were no jobs around here. They got out safe. But poor wee Gordon, it's a tragedy. He had his whole life ahead of him. I blame the UK government. He should never have been out there."