Why did Thomas Hobbes believe a sovereign was not bound by the social contract?

In the political philosophy of Thomas Hobbes, the sovereign is not bound by the social contract because the sovereign is not a party to the agreement.1

According to Hobbes, the social contract is a collective agreement made among individuals in the state of nature to transfer their right of self-government to a central authority in exchange for physical safety and security. Because the sovereign receives this power as a gift from the subjects and makes no promises in return, the sovereign remains outside the contract.1

Consequently, the sovereign is not subject to the laws they create, as they retain the total liberty that the subjects have traded away. For Hobbes, this absolute authority is essential; he argued that if the sovereign were bound by law or if power were divided, the resulting instability would risk returning society to a state of war. The only exception to this absolute obedience is if the sovereign fails to protect the subjects' lives, as the fundamental purpose of the contract is the preservation of the individual.123