During an online church service streamed in Sydney, Bishop Mar Mari Emmanuel of Christ the Good Shepherd Church and several other members were stabbed.
Members of the congregation began screaming and rushed to rescue the bishop.
The New South Wales Police said a man was arrested in connection with the incident, adding that four people were injured in the attack.
Sky News reports that a man in his 50s who suffered multiple lacerations was rushed to hospital in a serious condition, along with a man in his 30s.
A police statement said: “A police operation is underway in Wakeley, following reports of a stabbing.
“Officers attached to Fairfield City Police Area Command attended a location on Welcome Street, Wakeley following reports a number of people were stabbed.
“Officers arrested a male and he is assisting police with inquiries.”