He also admitted the possession of a claw hammer in a public place without a reasonable excuse.
The court heard Morrison and his partner Tracy Hamilton were drinking alcohol with Whitelaw at their house the previous day.
Morrison fell asleep amid claims Mr Whitelaw had stolen from him and took no further action.
Miss Hamilton and another person attended the nearby shop on Cumbernauld Road the next day and bumped into Mr Whitelaw.
Prosecutor Claire Wallace said: “He was noted to be wearing trainers belonging to the accused.”
Miss Hamilton sent the other person to fetch Morrison who attended the shop armed with a black-handled clawhammer.