He walks up to the priest, who has a cross in his hand and is reading from a text, pulls out his knife and starts stabbing him furiously, shows a video, as a shocked congregation at a church in Sydney let out a collective shriek.
This is the second stabbing incident in Sydney in three days.
The attacker has been arrested, said police.
The video shows the people rushing to help the priest and overpowering the knife-wielding attacker.
Emergency services said four people are being treated for “non-life threatening injuries”, reported news agency AFP
Local media said the incident occurred at the Christ the Good Shepherd Church.
In the first incident on Saturday, the police ruled out terror or ideology as a motive after a man killed six people in a random stabbing attack in one of Sydney’s busiest shopping centres.