"...it traineth each thing according to the quality of that thing ..."

"It is clear to thine Eminence that all the variations which the wayfarer in the stages of his journey beholdeth in the realms of being, proceed from his own vision. We shall give an example of this, that its meaning may become fully clear: Consider the visible sun; although it shineth with one radiance upon all things, and at the behest of the King of Manifestation bestoweth light on all creation, yet in each place it becometh manifest and sheddeth its bounty according to the potentialities of that place. For instance, in a mirror it reflecteth its own disk and shape, and this is due to the sensitivity of the mirror; in a crystal it maketh fire to appear, and in other things it showeth only the effect of its shining, but not its full disk. And yet, through that effect, by the command of the Creator, it traineth each thing according to the quality of that thing, as thou observest.

In like manner, colors become visible in every object according to the nature of that object. For instance, in a yellow globe, the rays shine yellow; in a white the rays are white; and in a red, the red rays are manifest. Then these variations are from the object, not from the shining light. And if a place be shut away from the light, as by walls or a roof, it will be entirely bereft of the splendor of the light, nor will the sun shine thereon."

-Bahá'u'lláh, The Seven Valleys And the Four Valleys, The Seven Valleys: Valley of Unity, pp. 18-19

Jenkins