‘Trying to obey the precepts is a hopeless task. The harder we try the more difficult it becomes. Gautama Buddha, Master Dogen, and the great patriarchs all gave up trying to obey the precepts. This sounds strange but it is true. They found they could not obey the precepts by their conscious efforts so they worked on the problem from another angle. They found that when they practiced Zazen every day their lives became simple and clear. They found in fact that they could not disobey the precepts.
In our life we must make our decisions moment by moment. They are instantaneous: they are dependent on the condition of our body and mind at the moment. Therefore when our body and mind are balanced and composed, our action reflects our composure. When we are `right’, our actions will also be right. So the only way to obey the precepts is to change our body and mind through the practice of Zazen. When we practice Zazen we resume our original nature – our Buddha-nature. We find ourselves in harmony with the Universe at every moment. In such a state it is impossible for us to break the precepts. When we practice Zazen we become persons who cannot disobey the precepts.’ (from a talk on the Precepts)
This is one of those expressions that needs careful attention paying to it, or else someone can come away thinking, oh, you can’t break the precepts, so that means you can do anything. Far from it.