A Quote by Lao Tzu on tao te ching, dao, eternal tao, nameless name, origin, source, mystery of mysteries, door of all essence, and the mother of all things

Tao can be talked about, but not the Eternal Tao.
Names can be named, but not the Eternal Name.
As the origin of heaven-and-earth, it is nameless:
As "the Mother" of all things, it is nameable.
So, as ever hidden, we should look at its inner aspects.
As always manifest, we should look at its outer aspects.
These two flow from the same source,
though differently named;
And both are called mysteries.
The Mystery of mysteries is the Door of all essence.