Paṭhamarahogatasutta
In Private (1st)
While meditating alone, Anuruddha reflected that one who has neglected the four kinds of mindfulness meditation has neglected the path to the end of suffering. Moggallāna reads his mind and visits to question him on this. Anuruddha speaks of developing the four kinds of mindfulness meditation internally and externally, in terms of origin and cessation, and developing power over perceptions.
Translations
Dutiyarahogatasutta
In Private (2nd)
While meditating alone, Anuruddha reflected that one who has neglected the four kinds of mindfulness meditation has neglected the path to the end of suffering. Moggallāna reads his mind and visits to question him on this. Anuruddha speaks of developing the four kinds of mindfulness meditation internally and externally.