Those who bring sunshine to the lives of others cannot keep it from themselves.

The line expresses a moral psychology of generosity: joy is not a finite commodity that diminishes when shared, but something that rebounds on the giver. “Sunshine” functions as a metaphor for warmth, encouragement, and hope—small acts of kindness that brighten another person’s day. The claim that one “cannot keep it from themselves” suggests an almost natural law: to practice benevolence is to place oneself in the path of the same light one offers. Read this way, the quote is both ethical counsel (be a source of good for others) and pragmatic reassurance (doing so will also nourish your own spirit).