Bhagavad Gita, Chapter 6, Verse 8

Whose heart is filled with satisfaction by wisdom and realisation, and is changeless, whose senses are conquered, and to whom a lump of earth, stone, and gold are the same: that Yogi is called steadfast.

When someone's contentment isn't tied to what they own or encounter, dirt and gold genuinely stop looking all that different.

This is a striking, deliberately extreme image. Real inner satisfaction is described as capable of flattening even something as culturally loaded as the difference between worthless dirt and precious gold, because neither one was ever the actual source of that person's peace.