What Heaven has conferred is called The Nature; an accordance with this nature is called The Path of duty; the regulation of this path is called Instruction. The path may not be left for an instant. If it could be left, it would not be the path.
To be constantly without desire is the way to have a vision of the mystery of heaven and earth. For constantly to have desire is the means by which their limitations are seen.
The way of Heaven and Earth may be completely declared in one sentence: They are without any doubleness, and so they produce things in a manner that is unfathomable.