Joshua Benjamin Guy went alone to the home of Jehovah's Witness Benjamin Jessop one night in May, 2014, in an effort to persuade him to agree with his girlfriend's interpretations of the Bible.

Guy's German partner had been studying the Bible alongside Mr Jessop, as part of her quest to join a religious group.

But the woman had disagreed with some of Mr Jessop's views, and Guy was worried it would lead her to leave Australia, and him.

"Because of these differences, it looked to you like she would not join his group," Justice Walter Sofronoff told Guy in the Brisbane Supreme Court on Tuesday.

"You became worried that if she was unable to find a religious group and join it, that she might leave Australia and go back to her home in Germany.

"You became worried that she might leave you, so that is why you went to Mr Jessop's home."

Guy apologised for turning up unannounced, and agreed to meet Mr Jessop the next day to discuss his views on the Bible.

Mr Jessop offered to drive Guy home, but on the way they got into an argument about a biblical passage.

Once there, Guy snapped, pulling out a knife and holding it against Mr Bessop's throat.

"You said, 'Are you going to tell me with a knife pressed against your throat that Satan is not going to burn in hell'?" Justice Sofronoff said.

"With great courage and conviction, Mr Jessop replied 'Yes, that is what I am going to say'.

"You then cut his throat."

The cut was so deep Mr Jessop's throat muscles were showing.

He told Guy he was dying, but Guy said: "It's not a death wound."

Guy said he would go with Mr Jessop to a hospital.

Mr Jessop tried to drive, but blood thinners he was taking meant he was bleeding profusely, and he became disoriented.

Mr Jessop fled the vehicle when Guy took the wheel and crashed into a parked car.

Guy chased him, still holding the knife, and tried to stop him from getting back into the car and driving away.

Mr Jessop was in court on Tuesday, along with members of Guy's family.

The court was told he was a resilient man who did not want to make a victim impact statement, and had overcome his injuries.

Guy, 32, who pleaded guilty to a malicious act with intent, was sentenced to seven years in prison, but can immediately apply for parole due to time already served.

Australian Associated Press