What will motivate us to obey the principle of utility? What is the source of its obligation? Where does it get its binding force from?

Principle of utility

What will motivate us to obey the principle of utility?

What is the source of its obligation? Where does it get
its binding force from?

What is its sanction? [= ‘What is the reward for conforming
to it and/or the punishment for not doing so?’] What are the motives to obey it?

What sort of proof can be given for the principle of utility?