Legal obligation is both Bentham's and Hart's central concern. Yet, Dworkin does not really make an account on this topic, but rather criticising positivist theses. Thus, I will first make a brief summary of Bentham's and Hart's account of legal obligation, before I make a comparison of all the three jurists' theories.
Jeremy Bentham's Legal Obligation
For Bentham, obligation is the opposite of rights. Obligations and rights are the two classes of things that the legislator distributes among the members of the community. "A right cannot be created in favour of anyone, without imposing a corresponding obligation on another." "To commit an offence is, on the one hand, to violate an obligation---on the other hand, a right."
Bentham regarded rights as a benefit, while obligations as "in themselves an evil" , because obligation placed constraints on people's personal liberty. As a utilitarian, Bentham believed that the function of law is the give the greatest happiness to the people in the community.
Since rights and obligations are opposite, when a right is conferred, at the same time an obligations is imposed. Thus, when a legislator legislates, he gives benefit and at the same time of imposing evil. He has to try his best to achieve what Bentham called the "greatest happiness". In other words, he has to find a balance between benefits and evil.
Bentham believed that "legal obligation was nothing more than an awareness of the probability that punishment would be imposed in accordance with a legal scheme." Legal obligation arisen when a sovereign gives commands to its subject backed by rewards or punishments. Hart summarizes Bentham's idea of command as:
"an expression by one person of the dsire that another person should do or abstain from some action, accompanied by a threat of punishment which is likely to follow...