P24: Acting absolutely from virtue is nothing else in us but acting, living, and preserving our being (these three signify the same thing) by the guidance of reason, from the foundation of seeking one’s own advantage.

Dem.: Acting absolutely from virtue is nothing but acting from the laws of our own nature (by D8). But we act only insofar as we understand (by IIIP3). Therefore, acting from virtue is nothing else in us but acting, living, and preserving one’s being by the guidance of reason, and doing this (by P22 C) from the foundation of seeking one’s own advantage, q.e.d.