4.
The Chapter on Searches
1-10.
The Ten Discourses Beginning with Searches
685-694. "There are these three searches, monks. Which three? Sensual seeking, seeking existence, seeking the holy life - these, monks, are the three searches. For the direct knowledge, full understanding, utter elimination, and abandoning of these three searches, the four right strivings are to be developed. Which four? Here, monks, a monk for unarisen... etc. he generates desire for the presence, non-decay, increase, expansion, development, and fulfilment of arisen wholesome mental states, he strives, arouses energy, exerts the mind, and strives. For the direct knowledge, full understanding, utter elimination, and abandoning of these three searches, these four right strivings are to be developed." The tenth.
The Search Chapter is the fourth.
Its summary:
Barrenness, stain, and trouble, feeling, craving, and with thirst.