[384] How is it that these three dhammas are not the object of a single mind (citta), and yet these three dhammas are not unknown, and the mind does not fall into distraction, and effort (padhāna) is evident, and one accomplishes the endeavor and attains distinction?
Suppose a tree trunk were laid on a level piece of ground, and a man were to cut it with a saw. The man's mindfulness (sati) is established by way of the saw's teeth where they touch the tree; he does not give attention to the saw's teeth as they come or as they go, yet the saw's teeth as they come or as they go are not unknown to him; and effort is evident, and he accomplishes the endeavor and attains distinction.
As the tree trunk laid on the level piece of ground, so is the sign of the binding [of mindfulness] (upanibandhanā-nimitta); as the saw's teeth, so are the in-breaths and out-breaths; as the man's mindfulness is established by way of the saw's teeth where they touch the tree, and he does not give attention to the saw's teeth as they come or as they go, yet the saw's teeth as they come or as they go are not unknown to him, and effort is evident, and he accomplishes the endeavor and attains distinction — even so, a bhikkhu sits having established mindfulness at the tip of the nose or on the sign of the mouth (mukhanimitta); he does not give attention to the in-breaths and out-breaths as they come or as they go, yet the in-breaths and out-breaths as they come or as they go are not unknown to him; and effort is evident, and he accomplishes the endeavor and attains distinction.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.