Provision
The right of private defence of the body commences as soon as a reasonable apprehension of danger to the body arises from an attempt or threat to commit the offence though the offence may not have been committed; and it continues as long as such apprehension of danger to the body continues.
Simply Put
This section means private defence of body starts at the point where fear or apprehension to body starts and it lasts till the point where apprehension or fear continues.