Which is it in the original Buddhist saying: "One thought is pure, the heart is like a lotus blooming" or "The heart is like a lotus blooming"? Or are both right?

The correct one is: The heart is like a lotus flower.

Excerpted from "One Flower, One World" "Buddha said: One flower is one world, one tree is one floating life, one grass is one paradise, one leaf is one Tathagata, one sand is one bliss, one square is one pure land, one smile is one "Every thought is pure."

It means: if there is nothing in the heart, the heart will be pure. One flower can fill the world. After understanding these, one flower and one grass is the whole world, and the whole world is as empty as flowers and grass, and a human mind can accommodate hundreds of rivers and people.