Bhagavad Gita, Chapter 13, Verse 34

As the one sun illumines all this world, so does He who abides in the Kshetra, O descendant of Bharata, illumine the whole Kshetra.

Something this small is described here as lighting up something enormously larger, one real image doing a lot of work.

Comparing the soul to the sun shows how a single, seated source can spread consciousness through an entire body. Real scale, tiny cause and vast effect, is made vivid through this one comparison.