an.5.60 Aṅguttara Nikāya (Numbered Discourses)

“Bhikkhus, it is rare to find one gone forth in old age who possesses five qualities. What five? It is rare to find one gone forth in old age (1) who is easy to correct; (2) who firmly retains in mind what he has learned; (3) who accepts instruction respectfully; (4) who can speak on the Dhamma; and (5) who is an expert on the discipline. It is rare to find one gone forth in old age who possesses these five qualities.”