The Person not larger than a thumb, the inner Self, is always settled in the heart of men. Let a man draw that Self forth from his body with steadiness, as one draws the pith from a reed. Let him know that Self as the Bright, as the Immortal; yes, as the Bright, as the Immortal.

In plain words: The inner Self, said to be no bigger than a thumb, always lives in the human heart. A person should patiently separate this Self from the body in their understanding, the way one pulls the soft inner stalk out of a reed. They should know it as shining and undying.