Dhammapada · 7.3

Yesaṃ sannicayo natthi, ye pariññātabhojanā;Suññato animitto ca, vimokkho yesa gocaro;Ākāseva sakuntānaṃ, gati tesaṃ durannayā.

Yesam sannicayo natthi, ye parinnatabhojana; Sunnato animitto ca, vimokkho yesa gocaro; Akaseva sakuntanam, gati tesam durannaya.

Those who have no accumulation, who fully understand food, whose domain is emptiness and the signless liberation — their path, like that of birds in the sky, is hard to trace.

— Dhammapada 7.3

Source: Pali text from the Khuddaka Nikāya of the Pali Canon (oldest extant Buddhist scripture, compiled c. 3rd century BCE). Public-domain English readings drawn from F. Max Müller's translation in Sacred Books of the East, Vol X (1881) and the Buddhist Publication Society's freely-licensed Acharya Buddharakkhita rendering.