Lay-down-the-law meaning

He needs to lay down the law.

He claimed to lay down the law everywhere, in the preliminary negotiations between his ambassador and the Spanish ambassador in London, in the affair of the salute exacted from French vessels by the English, and in that of the Corsican guard in Rome; while he proposed to become the head of the crusade against the Turks in the Mediterranean as in Hungary.

Ethics have become more distinctively a science, instead of an awkward hybrid between a science and an art; their business has been to investigate what moral conduct is, not to lay down the law as to what it ought to be.

They must be prepared to support, encourage, and lay down the law from time to time to keep the company moving forward.