Thomas Main, 41, was sentenced to life imprisonment and ordered to serve at least 17 years and six months behind bars for killing 55-year-old Francis McGrow - the brother of Tam "The Licencee" McGraw, who died in 2007.
The High Court in Glasgow heard that Mr McGrow was stabbed in the back three times by Main, who described himself to police as his "best pal".
Then as Mr McGrow lay helpless on the floor of his living room at Hermiston Road in Springboig, Glasgow, Main knifed him a further 37 times.
No motive for the killing came out in court.
Yesterday, judge Lord Armstrong told Main: "This was a vicious attack when your victim was lying on his back and unable to defend himself. There are no reasons which could possibly justify the taking of another's life as you did."
The court heard that Mr McGrow, who had changed his name from McGraw, was murdered between October 26 and 27 last year. Main was out of bail at the time and Mr McGrow had allowed him to stay in his home.
After carrying out the deadly attack Main disposed of the knife and tried to hide his jeans, which had Mr McGrow's blood on them.
He then travelled into the city and made a call from a phone box in Gallowgate, Glasgow, saying that Mr McGrow had been murdered.
Advocate depute Adrian Cottam, prosecuting, told the court Main had a number of convictions for dishonesty and drugs offences.