In plain words
He grew fed up. He took the cows. He came home. He came to his mother and cried. “Mother! Somebody in that hill, some other fellow or some animal, is talking. Whatever word I speak, he answers back with the very same word. However I scold him, he scolds back in just the same way. He is not a grown-up. I think he is perhaps just my age. What right has he to scold me! We must go and punish him,” he told his mother. “Tomorrow I will come along with you, my son! I will test who he is,” she said. The mother went with the boy the next day. First of all he played the flute. Back came the resound of the flute. Look! He's playing back just like me. Again he gave a shout. Back came another shout. Then: look, Mother! This fellow is insulting me like this. The mother understood it all. “This is nothing else; inside this hill there is an echoing stone. Apart from that, there is no other person here,” the mother said. The whole hill, all of it, is nothing but stone. The whole sea is nothing but water. The whole forest is nothing but wood. The whole earth is nothing but Brahman. The whole body is nothing but flesh. When you rightly recognise the principle of these five elements, no other person criticises at all. So if you say someone is criticising, this Prakṛti has the power of Reaction, Reflection, Resound. So the influence of Prakṛti alone is the root cause of these two, and nothing else. Bring such Prakṛti under your control; you must not come under the control of this Prakṛti. Only then will you become victorious. Our body itself is Prakṛti. We must not come under the control of the body. We must bring this body under our own control. When we control the body, the mind too comes under control. Only then does the form of the Ātma come into view.
Demon nature, animal nature, humanness, divinity
When we forget the Ātma and the mind and keep merely the body alone in view, this turns into nothing but demon nature. If we give up the Ātma and keep only the mind and the body, this takes shape as animal nature. When we keep the three, body, mind and Ātma, as one, it takes shape as humanness.