The legal norm that killing another person is prohibited is a primary rule that is implied in the legal norm that killing another person is punishable with maximum detention of 4 years, which is a secondary rule. The latter norm recognises the former; it attributes the legal power to punish to the courts.
The legal norm that a valid contract must be performed may be enforced by the legal norm that failure to perform may result in an obligation to pay compensation due to breach of contract.
The legal norm that renovation of one’s house requires a building permit is part of administrative law and may be enforced by way of a legal norm that imposes a fine or allows for an order to undo the renovation.
The Rule of Law means that legal norms cannot be applied in an arbitrary manner, based on the whims of a government official or depending on the benevolence of a judge.