Prayers were said at St Andrew's Cathedral in Clyde Street yesterday afternoon, after the Archbishop of Glasgow, Philip Tartaglia announced the news to his congregation.
He later said: "Everybody is just shocked.
"Members of the clergy were texting me immediately when they found out this morning.
"Nobody expected this and certainly not today, there was no real forewarning."
As people were leaving the church some were surprised while others were saddened.
Mary Malley, 75, who is from Saltmarket and works in the Cathedral shop, said "I was surprised, that's all.
"I don't think it'll have any impact on the church, things will just continue in the same way but it all depends on who the next Pope is.
"I thought Pope Benedict was very good."
Samuel Donald, 80, from Toryglen said: "It's a very sad occasion.
"Unfortunately he wasn't doing too well with his health and we just have to accept that.
"He was very traditional but he introduced some new things too; he was a really good Pope.
"I went to see him when he came to Glasgow in 2010, and it was a fantastic experience."
In a statement made by the Pope yesterday, he announced his resignation from the papal office due to his age, admitting his strengths were 'no longer suited to an adequate exercise of the Petrine ministry.'
Most Vatican watchers said they didn't think it would have any impact on the church as a whole.
John Coyle, 81, retired, from Glasgow, said: "Things are in flux right now, it's very difficult to deal with. I hope we have a new Pope for Easter.
"It's been a very long time since a Pope resigned, and I thought Pope Benedict was the right man for the job."
Irene Cullen, retired from the West End, said: "Never in my lifetime have I know a Pope to retire, so his health must be fairly bad as he's quite old.
"The last Pope was ill for so long, and he might have found that quite a trial as there was a lot he couldn't do.
"Pope Benedict was the previous Pope's best advisor so maybe he looked at it and thought he didn't want to end up like that.
"I'm not sure who will be the next Pope, maybe Cardinal Keith O'Brien but it's hard to say."
Marie Duffy, 58, from the city centre, said: "I didn't know until the Archbishop mentioned it at the mass.
"I know he's a good age, God help him, it's just a real shame as he's not been in good health.
"The church will just move on, and the next Pope could be a total change."
Frank Brady, 81, of Glasgow, said: "He's been there for eight years but it seems like he's been a new Pope.
"I don't think it'll make much difference to the Catholic church, it depends who the next Pope is, he will maybe start something else.
"This Pope was interested in bringing tradition back to the church, particularly with music in the masses.
"He was a very good Pope, he took an interest in things that mattered, traditional things, yet he was still up to date with what was going on."
The news was even a surprise to Archbishop Tartaglia, who said: "Sometimes Bishops get some sort of forewarning of major news in the church but there was not even a whisper, so I was shocked too.
"I remember him from my own personal contact, and I'll miss him.
"His teaching and writing have been every influential in my life as a Bishop, and I look to him for inspiration."
Speaking about the future, the Archbishop, said: "Usually when a Pope goes, it is because he dies.
"This Pope won't be dead, he'll be alive and there will be all kinds of speculation about what he'll do next, where he's going to live and how he's going to live.
"I suppose in the next wee while details will emerge of how and where he's going to live.
"One thing I don't have is a clear idea of who the next Pope will be.
"I must go and look at the College of Cardinals and work that out, as there's isn't one person who immediately comes to mind."