Barrel maker planes staves to exact angles.
His shavings glow in the afternoon sun.
He joins fragrant wood together,
Fitting shoulders like building an arch.
Until the bands, there is no barrel.
There is no barrel until the cooper builds it. Until then, there are pieces of straight-grained wood, shavings, a round bottom, and metal bands, but there is no barrel. All parts are there, but they need to be composed in order to take shape. It is the same with the facets of our personalities. Until they are held tightly together as a single unit, there is no completeness, and usefulness will not be forthcoming.
Spiritual practice can be the outside order that the personality needs. While such an order can be initially restricting, perhaps even feel artificial in its arbitrariness, it is absolutely necessary. It is a means to an end. Perhaps at the end we will not need such structure, but neither will we reach the end without the means. Before we leave the image of the barrel, there is one more thing to notice about it. A barrel encloses only one thing : void. That is the way it is with us, too. All the pieces of our personality, no matter how perfectly formed, only enclose what is inside us. All spiritual practice, while it may bind us into a cohesive whole, points to the emptiness of the center. This emptiness is not nihilism but the open possibility for Tao to enter. Only with such space will we have peace.