State or sovereign as source of law
From Textop Wiki
The sovereign is the only legislator, and therefore the only source of law, in any State.
The legislator in all Commonwealths is only the sovereign, be he one man, as in a monarchy, or one assembly of men, as in a democracy or aristocracy. For the legislator is he that maketh the law. And the Commonwealth only prescribes and commandeth the observation of those rules which we call law: therefore the Commonwealth is the legislator. But the Commonwealth is no person, nor has capacity to do anything but by the representative, that is, the sovereign; and therefore the sovereign is the sole legislator. For the same reason, none can abrogate a law made, but the sovereign, because a law is not abrogated but by another law that forbiddeth it to be put in execution.
Hobbes, Lev XXVI 5
The authority of law derives from a conquering sovereign, even if the conquering sovereign does not change the written laws of the conquered country.
If the sovereign of one Commonwealth subdue a people that have lived under other written laws, and afterwards govern them by the same laws by which they were governed before, yet those laws are the civil laws of the victor, and not of the vanquished Commonwealth. For the legislator is he, not by whose authority the laws were first made, but by whose authority they now continue to be laws. And therefore where there be diverse provinces within the dominion of a Commonwealth, and in those provinces diversity of laws, which commonly are called the customs of each several province, we are not to understand that such customs have their force only from length of time; but that they were anciently laws written, or otherwise made known, for the constitutions and statutes of their sovereigns; and are now laws, not by virtue of the prescription of time, but by the constitutions of their present sovereigns. But if an unwritten law, in all the provinces of a dominion, shall be generally observed, and no iniquity appear in the use thereof, that law can be no other but a law of nature, equally obliging all mankind.
Hobbes, Lev XXVI 9
To the objection that the common law has no controlling authority other than Parliament.
Seeing then all laws, written and unwritten, have their authority and force from the will of the Commonwealth; that is to say, from the will of the representative, which in a monarchy is the monarch, and in other Commonwealths the sovereign assembly; a man may wonder from whence proceed such opinions as are found in the books of lawyers of eminence in several Commonwealths, directly or by consequence making the legislative power depend on private men or subordinate judges. As for example, that the common law hath no controller but the Parliament; which is true only where a parliament has the sovereign power, and cannot be assembled nor dissolved, but by their own discretion. For if there be a right in any else to dissolve them, there is a right also to control them, and consequently to control their controllings. And if there be no such right, then the controller of laws is not parlamentum, but rex in parlamento. And where a parliament is sovereign, if it should assemble never so many or so wise men from the countries subject to them, for whatsoever cause, yet there is no man will believe that such an assembly hath thereby acquired to themselves a legislative power. Item, that the two arms of a Commonwealth are force and justice; the first whereof is in the king, the other deposited in the hands of the Parliament. As if a Commonwealth could consist where the force were in any hand which justice had not the authority to command and govern.
Hobbes, Lev XXVI 10