Omnis virtus humana vel est intellectualis vel moralis quia principium humanorum actuum in homine non est nisi duplex, scilicet intellectus sive ratio, et appetitus, haec enim sunt duo moventia in homine, ut dicitur in III de anima.
Every human virtue is either intellectual or moral because in man there are but two principles of human actions, viz. the intellect or reason and the appetite: for these are the two principles of movement in man as stated in De Anima iii, text. 48.
Unde omnis virtus humana oportet quod sit perfectiva alicuius istorum principiorum. Si quidem igitur sit perfectiva intellectus speculativi vel practici ad bonum hominis actum, erit virtus intellectualis, si autem sit perfectiva appetitivae partis, erit virtus moralis.
Consequently every human virtue must needs be a perfection of one of these principles. Accordingly if it perfects man's speculative or practical intellect in order that his deed may be good, it will be an intellectual virtue: whereas if it perfects his appetite, it will be a moral virtue.
Prudentia, secundum essentiam suam, est intellectualis virtus. Sed secundum materiam, convenit cum virtutibus moralibus, est enim recta ratio agibilium, ut supra dictum est. Et secundum hoc, virtutibus moralibus connumeratur.
Prudence is essentially an intellectual virtue. But considered on the part of its matter, it has something in common with the moral virtues: for it is right reason about things to be done, as stated above (q57 a4).