Rev. Hyeon Soo Lim was released from a North Korean prison on Wednesday and spoke to the Light Presbyterian Church in Ontario.
Lim was subject to a harsh life of labour in solitary confinement, where he was forced to dig holes in frozen ground for two winters.
The pastor told members of his church that during his imprisonment in North Korea he broke three metal spades after he was ordered to dig through frozen mud.
According to Canadian news outlet The Globe and Mail, Lim said: "During the winter, I had to dig holes that measured one metre wide and one metre deep. The ground was frozen.
"The mud was so hard that it took two days to dig one hole. It was incredibly challenging. My upper body was sweating. My fingers and toes were frostbitten."
During his first year in captivity he had no Bible so he read more than 100 books and watched over 300 films, all of them about North Korea.
He then received Korean and English Bibles, which he used to memorise more than 700 verses. Lim said he was glad to be at his home church after worshiping alone for 130 Sundays, although he was grateful for an extended time of solitude with God.
He added: "God gave me the ability to imagine. When you don't watch TV or read the newspaper, there's a lot of time."
Lim said he suspected his life sentence was commuted to reduce the global pressure on Pyongyang in recent days.
On Tuesday a delegation led by Canada's national security adviser, Daniel Jean, arrived in Pyongyang to discuss Lim's imprisonment, according to the office of Canadian Prime Minister Justin Trudeau.
The pastor was grateful towards his adopted country.
He told his congregants in his native language of Korean: "It's a miracle for me to be here today. I always knew Canada was a very warm and compassionate nation, but through my ordeal I really began to grasp that very deeply."