Which ancient book does "Invisible Love" come from?

The word "great love is invisible" evolved from the word "elephant is invisible"

"Elephant is invisible" comes from the forty-first chapter of Laozi's Tao Te Ching.

When talking about the highest realm of Tao, Laozi quoted the saying that "generosity has no horns, magnificence is a late bloomer, loud and joyful, and elephants are invisible", which means: "The grand founder (image) generally can't see the edges and corners, the grand materials (things) generally mature late, the grand melody often sounds thin, and the grand momentum scene seems to have no certain shape." "Elephant invisibility" can be understood as: the world's greatest magnificent style and realm, often not rigidly adhere to certain things and patterns, but show a "colorful" face and scene.