Let understanding illuminate whatever receives it

The George Long translation of 1862:

The sun appears to be poured down, and in all directions indeed it is diffused, yet it is not effused. For this diffusion is extension: Accordingly its rays are called Extensions because they are extended But one may judge what kind of a thing a ray is, if he looks at the sun's light passing through a narrow opening into a darkened room, for it is extended in a right line, and as it were is divided when it meets with any solid body which stands in the way and intercepts the air beyond, but there the light remains fixed and does not glide or fall off. Such then ought to be the out-pouring and diffusion of the understanding, and it should in no way be an effusion, but an extension, and it should make no violent or impetuous collision with the obstacles which are in its way, nor yet fall down, but be fixed and enlighten that which receives it. For a body will deprive itself of the illumination, if it does not admit it. Marcus Aurelius.  Meditations.  Book 8.

Chrystal's 2017 rendering based on the Foulis translation of 1742:

The sun seems to us diffused everywhere, pervasive of all things, yet never exhausted. This diffusion is a sort of extension, and hence the Greek word for rays is thought to be derived. You may observe the nature of a ray if you see it entering through some small hole into a darkened chamber. Its direction is straight, and it is reflected around when it falls upon any solid body, which shuts it off from the air beyond. There it stands and does not slip or fall. Now, such should be the flow and diffusion of the understanding, never exhausted, always extending; not violently or furiously dashing against the obstacles that meet it, nor falling aside, but resting there and illuminating whatever will receive it. That which will not transmit the light does but deprive itself of radiance. Marcus Aurelius.  Meditations.  Book 8.

Image: Greek Silver Kylix Depicting Helios driving a Chariot. Found in Panticapaeum (ancient Taurica - modern Kerch), first half of the 3rd century BCE (Hermitage Museum, St. Petersburg, Russia)