Objection 1. It would seem that justice is not a general virtue. For justice is specified with the other virtues, according to Wisdom 8:7, "She teacheth temperance and prudence, and justice, and fortitude." Now the "general" is not specified or reckoned together with the species contained under the same "general." Therefore justice is not a general virtue.
Objection 2. Further, as justice is accounted a cardinal virtue, so are temperance and fortitude. Now neither temperance nor fortitude is reckoned to be a general virtue. Therefore neither should justice in any way be reckoned a general virtue.
Objection 3. Further, justice is always towards others, as stated above (Article 2). But a sin committed against one's neighbor cannot be a general sin, because it is condivided with sin committed against oneself. Therefore neither is justice a general virtue.
On the contrary, The Philosopher says (Ethic. v, 1) that "justice is every virtue."
I answer that, Justice, as stated above (Article 2) directs man in his relations with other men. Now this may happen in two ways: first as regards his relation with individuals, secondly as regards his relations with others in general, in so far as a man who serves a community, serves all those who are included in that community. Accordingly justice in its proper acceptation can be directed to another in both these senses. Now it is evident that all who are included in a community, stand in relation to that community as parts to a whole; while a part, as such, belongs to a whole, so that whatever is the good of a part can be directed to the good of the whole. It follows therefore that the good of any virtue, whether such virtue direct man in relation to himself, or in relation to certain other individual persons, is referable to the common good, to which justice directs: so that all acts of virtue can pertain to justice, in so far as it directs man to the common good. It is in this sense that justice is called a general virtue. And since it belongs to the law to direct to the common good, as stated above (I-II, 90, 2), it follows that the justice which is in this way styled general, is called "legal justice," because thereby man is in harmony with the law which directs the acts of all the virtues to the common good.
Reply to Objection 1. Justice is specified or enumerated with the other virtues, not as a general but as a special virtue, as we shall state further on (A07,12).
Reply to Objection 2. Temperance and fortitude are in the sensitive appetite, viz. in the concupiscible and irascible. Now these powers are appetitive of certain particular goods, even as the senses are cognitive of particulars. On the other hand justice is in the intellective appetite as its subject, which can have the universal good as its object, knowledge whereof belongs to the intellect. Hence justice can be a general virtue rather than temperance or fortitude.
Reply to Objection 3. Things referable to oneself are referable to another, especially in regard to the common good. Wherefore legal justice, in so far as it directs to the common good, may be called a general virtue: and in like manner injustice may be called a general sin; hence it is written (1 John 3:4) that all "sin is iniquity."
Source: Summa Theologica (New Advent)