Hart believes that there are two different types of rules that comprise the "essence" of law: primary rules and secondary rules Primary rules are "duty imposing" rules. They impose certain specific duties upon the citizens of a state to act in a certain manner, or they may be subject to certain legal sanctions. Hart characterizes primary rules as "basic" rules. They tell the citizen what one can and cannot do under the law.'
For instance, laws setting speed limits, laws prohibiting trespassing are examples of primary rules. Primary rules are generally what the ordinary citizen means when he refers to something as "the law." Through rules, the social acceptance predominates.
The acceptance of primary rules is the result of a bonding by way of kinship/trust/common sentiments/faith and not by authoritative ways. However, there would be defects inherent in a social structure based on primary rules only. It will be uncertain, static and inefficient. (International law)