[366] *(paragraph number editorial, from the edition's numbering; not present in the Pali excerpt supplied)*
Which eighteen mental defilements (upakkilesa) arise?
When one follows with mindfulness the beginning, middle, and end of the in-breath (assāsa), the mind (citta) gone to distraction internally is an obstacle to concentration (samādhi). When one follows with mindfulness the beginning, middle, and end of the out-breath (passāsa), the mind gone to distraction externally is an obstacle to concentration. Longing for the in-breath, delight (nikanti), and the conduct of craving (taṇhā) are an obstacle to concentration. Longing for the out-breath, delight, and the conduct of craving are an obstacle to concentration. For one overwhelmed by the in-breath, infatuation upon obtaining the out-breath is an obstacle to concentration. For one overwhelmed by the out-breath, infatuation upon obtaining the in-breath is an obstacle to concentration.
Following after the in-breath, following after the out-breath,
mindfulness gone to distraction internally, longing,
and straying to distraction externally—
these six are mental defilements of the concentration of
mindfulness of breathing (ānāpānassati-samādhi);
for one who wavers because of them, if the mind is not liberated,
then, not understanding liberation (vimokkha),
they remain dependent upon others.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.