We must now consider injustice, under which head there are four points of inquiry:
(1) Whether injustice is a special vice?
(2) Whether it is proper to the unjust man to do unjust deeds?
(3) Whether one can suffer injustice willingly?
(4) Whether injustice is a mortal sin according to its genus? _______________________
FIRST ARTICLE [II-II, Q. 59, Art. 1]
Whether Injustice Is a Special Virtue?
Objection 1: It would seem that injustice is not a special vice. For it is written (1 John 3:4): "All sin is iniquity [*Vulg.: 'Whosoever committeth sin, committeth also iniquity; and sin is iniquity']." Now iniquity would seem to be the same as injustice, because justice is a kind of equality, so that injustice is apparently the same as inequality or iniquity. Therefore injustice is not a special sin.
Obj. 2: Further, no special sin is contrary to all the virtues. But injustice is contrary to all the virtues: for as regards adultery it is opposed to chastity, as regards murder it is opposed to meekness, and in like manner as regards the other sins. Therefore injustice is not a special sin.
Obj. 3: Further, injustice is opposed to justice which is in the will. But every sin is in the will, as Augustine declares (De Duabus Anim. x). Therefore injustice is not a special sin.