There is a remark somewhere in Popper - but of course I forget where, and since I'm only struggling to remember this as an intro or lead-in I may even have made it up - to the effect that deep inquiry into the meaning of words is largely fruitless. And this is in the context of his attack on Plato, so my forward-reference to Plato spending an entire book trying to define Justice is apt.
The kind of thing I mean is Plato's Concept Of Justice: An Analysis which just happened to be the top google hit, and now I've propelled it higher. Plato doesn't really mean Justice, to be fair. He means a whole pile of things including morality, and the correct social order, which rather importantly included people like Plato being on top.
However, I'm ranting again. All I meant to say was that Hobbes rather beautifully turns this all around. First, in a State of Nature the notion of justice is absent:
To this warre of every man against every man, this also is consequent; that nothing can be Unjust. The notions of Right and Wrong, Justice and Injustice have there no place. 
But we're interested in people in a society, so we have the succinctly titled "Justice And Injustice What" section, wherein he says:
And in this law of Nature, consisteth the Fountain and Originall of JUSTICE. For where no Covenant hath preceded, there hath no Right been transferred, and every man has right to every thing; and consequently, no action can be Unjust. But when a Covenant is made, then to break it is Unjust: And the definition of INJUSTICE, is no other than The Not Performance Of Covenant. And whatsoever is not Unjust, is Just. 
And the key, in case you missed it, is "And whatsoever is not Unjust, is Just."
(perhaps you also need to know the immeadiately preceeding The Third Law Of Nature, Justice: From that law of Nature, by which we are obliged to transferre to another, such Rights, as being retained, hinder the peace of Mankind, there followeth a Third; which is this, That Men Performe Their Covenants Made: without which, Covenants are in vain, and but Empty words; and the Right of all men to all things remaining, wee are still in the condition of Warre.
Anyway, at least you know what Hobbes is on about: it certainly beats the wordy windbagging twaddle of Plato (Justice implies superior character and intelligence while injustice means deficiency in both respects. Therefore, just men are superior in character and intelligence and are more effective in action. As injustice implies ignorance, stupidity and badness, It cannot be superior in character and intelligence... Plato prove that justice does not depend upon a chance, convention or upon external force. It is the right condition of the human soul by the very nature of man when seen in the fullness of his environment. etc. etc.).
And this in turn is sparked off by Ralph Cudworth (it seems very odd that he was called Ralph) who in seeking to refute a variety of what he regards as heretical notions, principally the notion that Morality might not be absolute (see-also [[Euthyphro dilemma]]) is moved to use Plato's complaints about the Protagoreans and others, who inexcusably believe that nothing can be absolutely just, but all is a matter of social convention. Which is quite ironic because Cudworth is doing his best to demolish Hobbes, but justice is about the only thing that Hobbes would take as absolute; for example which books of religion you trust is (for Hobbes) clearly a matter of societal choice. But not for Cudders.
[I was going to try to avoid doing a review of 2011 by doing a review of "posts I wrote but didn't post in 2011. But I didn't find many. I did find this though. Written in February.]
The Open Society and Its Enemies: Vol I: Plato, chapter 3 part vi, I think, is the source you're seeking.
[Thank you -W]
Funny this should pop up now because I'm honest to goodness right in the middle of a reading through Republic. I'd just gotten past the bit about how a just society would certainly have people working only in assigned roles, arranged and communal marriages, eugenics, and infanticide, and finished up with the part in which Plato lays out that the easiest way to bring such an ideal and just society about is to have philosophers as rulers.
There's a delicious irony in it from my modern perspective.
Plato was the original fascist.
[That is certainly Popper's view. Heinlein thought he was a Commie (Plato, not Popper) -W]
Justice only applies between equals. Why should that be so?
[Not in Hobbes scheme. I don't see how you read that -W]
Heinlein thought he was a Commie
Heinlein thought everyone was a commie, not surprising, given his ultra-extreme libertarian views (re-read "The Moon is a Harsh Mistress" for an example of his utopian libertarian beliefs).
[I've just re-read Starship Troopers, which is much the same -W]
William --- Check what the Athenians said.
> insulating all remaining cavity walls and lofts.
Be warned: "Regardless of the wall assembly, exterior climate and indoor humidity, the same trends will always hold: adding insulation value to the exterior decreases condensation risk, adding air-permeable insulation value to the stud space increases the risk of condensation"
[That sounds very US-centric, and probably reflects your building construction. Insulating cavity (either retro-fit, by pumped-in fibre or some such; or new-build sheeting) is standard over here -W]