Ira non est in concupiscibili, sed in irascibili, quia ira respicit duo obiecta: scilicet vindictam, quam appetit, et eum de quo vindictam quaerit; et circa utrumque quandam arduitatem ira requirit: non enim insurgit motus irae, nisi aliqua magnitudine circa utrumque existente; "quaecumque enim nihil sunt, aut modica valde nullo digna aestimamus", ut dicit philosophus, in II Rhetoric.
Anger is not in the concupiscible, but in the irascible faculty, because anger regards two objects: viz. the vengeance that it seeks, and the person on whom it seeks vengeance; and in respect of both, anger requires a certain arduousness: for the movement of anger does not arise, unless there be some magnitude about both these objects; since "we make no ado about things that are naught or very minute," as the Philosopher observes (Rhet. ii, 2).
Ira dicitur componi ex tristitia et desiderio, non sicut ex partibus, sed sicut ex causis. Dictum est autem supra quod passiones concupiscibilis sunt causae passionum irascibilis.
Anger is said to be composed of [the concupiscible passions] pain and desire, not as though they were its parts, but because they are its causes. For it has been said above (q25 a2) that the concupiscible passions are the causes of the irascible passions.
Ira dicitur crescere in odium, non quod eadem numero passio quae prius fuit ira, postmodum fiat odium per quandam inveterationem, sed per quandam causalitatem. Ira enim, per diuturnitatem, causat odium.
Anger is said to grow into hatred, not as though the same passion which at first was anger, afterwards becomes hatred by becoming inveterate, but by a process of causality. For anger when it lasts a long time engenders hatred.