We proceed to the eighth article thus:

1. It seems that charity is not the form of the virtues. The form of a thing is either its exemplary form or its essential form. But charity is not the exemplary form of the other virtues. If it were so, the other virtues would necessarily belong to the same species as charity. Neither is it their essential form. If it were so, it could not be distinguished from them. Hence charity is in no wise the form of the virtues.

2. Again, in Eph.3:17 charity is compared to the root and the ground of the other virtues, "being rooted and grounded in love." Now a root or a ground has the nature of a material element, rather than of a form, since it is the first part to be made. Hence charity is not the form of the virtues.

3. Again, 2 Physics, text 70, makes it plain that form, end, and efficient cause [73] are not numerically identical. Now charity is said to be the mother of the virtues. We should not then say that it is their form.

On the other hand: Ambrose implies that charity is the form of the virtues (Commentary on Corinthians).

I answer: in moral matters, the form of an action depends principally on the end. The reason for this is that the principle of moral actions is the will, whose object, and as it were whose form, is the end. But the form of an action always depends on the form of the agent. In moral matters, therefore, what gives an action its form is the agency which directs it to its end. Now the preceding article made it clear that charity directs the actions of all other virtues to the ultimate end. It is therefore charity that gives their form to the actions of all other virtues. In this same sense it is said to "be the form of the virtues" since we speak of the virtues in relation to their actions as formed.

On the first point: charity is said to be the form of the other virtues neither as their exemplary form nor as their essential form, but rather as their efficient cause, in as much as it gives a form to each of them, as we have explained.

On the second point: charity is compared to a ground and a root because all other virtues are sustained and nourished by it, not because a ground and a root have the nature of a material cause.

On the third point: charity is said to be the end of the other virtues because all other virtues serve the end of charity. It is said to be the mother of the other virtues because it conceives the actions which it commands in them out of desire for the ultimate end, as a mother conceives in herself by another.

[73] See Q. 27, Art. 3, infra.