“Fas et nefas ambulant passu pene pari / prodigus non redimit vitium avari / virtus temperantia quadam singulari / debet medium / ad utrusque vitium / caute contemplari” (Justice and injustice proceed together, the person who dissipates does not redeem the vice of the stingy, while virtue, with rare temperance, must stay in the middle and watch over the vice on both sides, carefully).   
These words reported under the Wheel of Fortune image in Carmina Burana code, emphasize the relation between Justice and Temperance since, as Cicero, who in De Officiis, considers Justice the most important virtue, affirms, it has to be temperate not to become a motive for useless quibbles.
According to this inseparable union, the two virtues are put side by side in the Clement II grave in the Cathedral of Bamberg.
Following Aristotle, Saint Thomas underlines the basic role of justice in social life: “As to moderate passions means to make them correspond to the rule of reason, in the same way to moderate external actions to respect others, means to adjust them in relation to the others, giving to everybody what has to be given in the right measure. When this adjustment is perfect, there is the special virtue of justice: and all virtues that contain this adjustment are subjective parts of justice. If this adjustment is partial, there is only a potential part of justice” (III Sent., d.33, q. 3, a. 4).
Like Aristotle, Saint Thomas as well distinguishes three principal forms of Justice: commutative, legal and distributive. The firs one concerns justice duties between private citizens, the second those duties of private citizens towards community, and the third those of society towards individuals .
Justice is the “Saint Virtue”, as it is described in the  band that encloses the Allegory of the Good Governance in the Public Palace in Siena. With its hands it holds the pan of a big balance, representing commutative and distributive justice, and above Wisdom, its eternal muse, dominates (figure 1).  
Anyway in tarots, Justice has not to be understood in its social meaning, since above all, and first of all, it defines the action of God, who is equal par excellence. Divine Justice shows itself in its fidelity to the Alliance, which is to help its people and give them salvation.
The expression “Justice of God” looses the legal sense it had at the beginning, and becomes  a synonym of mercy, clemency and salvation (Genesis 18, 25; Deuteronomy 32,4).
It is above all Saint Paul who theorizes the doctrine of Justice based upon the goodness of God, upon mercy and faith, against the one based upon law (compare Romans 4, 6; Galatians 5,5).
We should not forget that in the first known order of Triumphs, the one reported in the Sermones de Ludo, Justice follows Judgment, to mean that in occasion of that event, Divine Justice will triumph, weighing souls and dividing the good ones from the bad ones and that goodness, mercy and clemency will have a predominant role.
Ripa says about "Divine Justice" in his Iconology: “A peculiarly beautiful woman, golden dressed with a gold crown on her head,  on which there is a dove surrounded by splendour, she will have long hair spread on her shoulders, with her eyes watching the world as if it were a low thing, holding a bare sword, in her right hand and scales in the left….scales mean that divine justice gives order to all the actions, the sword gives  punishment to delinquents…She looks at the world as if it were a small thing, since nothing is more than her…” (ed. 1669, pages 246-247).
The iconography of Justice is usually formed by a sitting woman who holds a sword and a balance in her hands, as it appears in Charles VI  Tarots (figure 2). The sword is always pointed towards the top, erect, and never bends, meaning that it will never have preferences, and will always be used as an instrument of defence of  just men. The balance symbolizes  the equity  which every human action will be judged with.
Other attributes are the Book of Law and sometimes a globe as well, symbol of power, as we find in  the Bologna Tarots in whole figures (figure 3 - Tarocchino Al Leone, 1770).
In the Visconti Sforza Tarots (figure 4) the upper part of the card shows a knight galloping with armour and sword. He is Archangel Michael, prototype of the Christian knight, often represented with sword and balance as we find in the Malatestian Temple in Rimini (figure 5).  He has the task of weighing the souls of the dead during the Universal Judgement (Apocalypse, VI, 2).