"Monks, when one quality is established in a monk, the five faculties are developed & developed well. Which one quality? Heedfulness.

"And what is heedfulness? There is the case where a monk guards his mind in with regard to [mental] fermentations and mental qualities accompanied by fermentations. When his mind is guarded with regard to fermentations and mental qualities accompanied by fermentations, the faculty of conviction goes to the culmination of its development. The faculty of persistence... mindfulness... concentration... discernment goes to the culmination of its development.

"This is how when one quality is established in a monk, the five faculties are developed & developed well."