What do you think, Reverend Ānanda? Is form permanent or impermanent?’ ‘Impermanent, reverend.’ ‘Is feeling … perception … choices … consciousness permanent or impermanent?’ ‘Impermanent, reverend.’ … ‘So you should truly see … Seeing this … They understand: “… there is nothing further for this place.”’ Reverends, the venerable named Puṇṇa son of Mantāṇī was very helpful to me when I was just ordained. He gave me this advice. And when I heard this teaching from Venerable Puṇṇa son of Mantāṇī, I comprehended the teaching.”

Linked Discourses 22.84 9. Senior Mendicants With Tissa

At Sāvatthī. Now at that time Venerable Tissa—the Buddha’s cousin on his father’s side—informed several mendicants: “Reverends, my body feels like it’s drugged. I’m disorientated, the teachings don’t spring to mind, and dullness and drowsiness fill my mind. I lead the spiritual life dissatisfied, and have doubts about the teachings.”

Then several mendicants went up to the Buddha, bowed, sat down to one side, and told him what had happened.