Meditations by Marcus Aurelius Book 10 Page 17

For these also, these famous soldiers and warlike men, if thou dost look into their minds and opinions, what do they for the most part but hunt after prey?

XI. To find out, and set to thyself some certain way and method of contemplation, whereby thou mayest clearly discern and represent unto thyself, the mutual change of all things, the one into the other. Bear it in thy mind evermore, and see that thou be throughly well exercised in this particular. For there is not anything more effectual to beget true magnanimity.

XII. He hath got loose from the bonds of his body, and perceiving that within a very little while he must of necessity bid the world farewell, and leave all these things behind him, he wholly applied himself, as to righteousness in all his actions, so to the common nature in all things that should happen unto him.