Asad Shah, 40, who ran a convenience store in the city’s Shawlands area, died following the attack by 32-year-old Tanveer Ahmed on March 24 this year.
At the High Court in Glasgow, Ahmed, from Bradford in West Yorkshire, admitted murdering Mr Shah.
Mr Shah, an Ahmadi Muslim who moved from Pakistan to Glasgow in 1998, was discovered outside his shop on Minard Road with stab wounds and taken to the Queen Elizabeth University Hospital, where he was pronounced dead.
The court was told that when Ahmed was interviewed under caution on March 25, he said his actions were motivated by Mr Shah’s decision to “disrespect the Koran, the Prophet Muhammad, Allah and Faith”.
Advocate depute Iain McSporran said: “He said that he had warned Asad Shah that he was there to kill him, had asked him to stop claiming to be a prophet, but that he had insisted he was.”
In a later statement he claimed Mr Shah, who was a popular community figure, had “disrespected the prophet of Islam, the messenger of Allah, Prophet Muhammad, peace be upon him.”
The statement added: “If I had not done this others would have and there would be more killings and violence in the world.
“I wish to make it clear that the incident was nothing at all to do with Christianity or any other religious beliefs. Even although I am a follower of Prophet Muhammad, peace be upon him, I also love and respect Jesus Christ.”
Mr Shah had wished Christians a Happy Easter on social media hours before his death but the court heard this had no bearing on the crime.