sn.22.149 Saṁyutta Nikāya (Linked Discourses)
Observing Not-Self
At Sāvatthī.“Mendicants, when a gentleman has gone forth out of faith, this is what’s in line with the teachings.
They should live observing not-self in form,
feeling,
perception,
choices,
and consciousness. …
They’re freed from suffering, I say.”