Dhamma Verses (Dhammapada, KN 2)

7: The Chapter about the Arahats – 94
The track of the liberated is hard to find
Ven. Belaṭṭhisīsa took to storing up food so as not to be
bothered with the almsround; the monks reported it to the
Buddha, who laid down a rule forbidding the storing of food,
and gave this teaching.
92. Yesaṁ sannicayo natthi, ye pariññātabhojanā,
suññato animitto ca vimokkho yesa’ gocaro,
ākāse va sakuntānaṁ, gati tesaṁ durannayā.
For those who have no stores,
who know their food aright,
for those whose resort is
the liberation that
is empty or signless,
like the birds in the sky,
their track is hard to find.