Osho did not have a single talk called "Es Dhammo Sanantano." This phrase appears across many discourses, but the primary series belongs to: – Volumes 1 through 12.
“You ask me, ‘What is the eternal law?’ Look at that bird flying in the sky. It leaves no footprints. The bird is not worried about scriptures. The bird simply flies. That flight is Dhammo. The sky is Sanantano. And the bird's trust in its own wings? That is Es. This... this whole existence... is the eternal law. Drop your borrowed knowledge. Drop your ‘shoulds’ and ‘should nots.’ Just listen to the law of your own heartbeat.” i--- Es Dhammo Sanantano Osho Audio Download UPD