Prudentia est virtus necessaria ad bene vivendum quia necesse est in ratione esse aliquam virtutem intellectualem, per quam perficiatur ratio ad hoc quod convenienter se habeat ad ea quae sunt ad finem. Et haec virtus est prudentia.
Prudence is a virtue necessary to lead a good life because an intellectual virtue is needed in the reason, to perfect the reason, and make it suitably affected towards things ordained to the end; and this virtue is prudence.
Prudentiae bonum attenditur in ipso agente, cuius perfectio est ipsum agere.
The good of prudence is in the active principle, whose activity is its perfection.
Cum homo bonum operatur non secundum propriam rationem, sed motus ex consilio alterius, nondum est omnino perfecta operatio ipsius, quantum ad rationem dirigentem, et quantum ad appetitum moventem. Unde si bonum operetur, non tamen simpliciter bene; quod est bene vivere.
When a man does a good deed, not of his own reason, but moved by the counsel of another, his deed is not yet quite perfect, as regards his reason in directing him and his appetite in moving him. Wherefore, if he do a good deed, he does not do well simply; and yet this is required in order that he may lead a good life.
Verum autem intellectus practici accipitur per conformitatem ad appetitum rectum. Quae quidem conformitas in necessariis locum non habet, quae voluntate humana non fiunt, sed solum in contingentibus quae possunt a nobis fieri, sive sint agibilia interiora, sive factibilia exteriora. Et ideo circa sola contingentia ponitur virtus intellectus practici, circa factibilia quidem, ars; circa agibilia vero prudentia.
The truth of the practical intellect depends on conformity with right appetite. This conformity has no place in necessary matters, which are not affected by the human will, but only in contingent matters which can be effected by us, whether they be matters of interior action, or the products of external work. Hence it is only about contingent matters that an intellectual virtue is assigned to the practical intellect, viz. art, as regards things to be made, and prudence, as regards things to be done.
Dicitur de divina sapientia, "sobrietatem et prudentiam docet, iustitiam et virtutem, quibus utilius nihil est in vita hominibus".
It is written (Wisdom 8:7) of Divine Wisdom: "She teacheth temperance and prudence and justice and fortitude, which are such things as men can have nothing more profitable in life."