摩訶止觀 2.113

2.113

答：譬如貧窮人得少便為足，更不願好者。若一種觀心，心若種種，當奈之何？此則自行為失。若用化他，他之根性舛互不同；一人煩惱已自無量，何況多人？譬如藥師集一切藥擬一切病。一種病人須一種藥治一種病，而怪藥師多藥。汝問似是。煩惱心病無量無邊，如為一人，眾多亦然。

Answer: It is like a poor man who, obtaining a little, is satisfied and seeks nothing better. If there is only one kind of contemplating the mind, what will you do if the mind takes on diverse forms? This would be a fault in one's own practice. If used to transform others, their faculties and dispositions are discordant and varied; the afflictions of a single person are already measureless, how much more so for many people? It is like a physician gathering all medicines in anticipation of all illnesses. A single patient needs a single medicine to treat a single illness, yet you wonder why the physician has so many medicines! Your question seems like that. The mental illnesses of affliction are limitless and boundless; as it is for one person, so it is for many.