What does 'nothing gold can say' relate to?

Answer 1

It relates to childhood and innocence I believe.

"Natures first green is gold" Stating natures children are born as, you guessed it, children.

"Her hardest hue to hold" Age is inevitable, you can't hold on to the hands of time

Answer 2

The phrase "nothing gold can stay" refers to the idea that all good things must come to an end, as nothing beautiful or perfect lasts forever. It often reflects the fleeting nature of youth, innocence, or moments of happiness in life. The phrase originates from a poem by Robert Frost, and has been interpreted to symbolize the inevitability of change and impermanence in the world.