This was said by the Blessed One, said by the Arahant, as I have heard:
“Bhikkhus, for a trainee bhikkhu whose mind has not yet attained the unsurpassed security from bondage, who is dwelling and aspiring for it, I do not see any other single external factor as so helpful as |good friendship::friendship with wholesome persons [kalyāṇamittatā]|. Bhikkhus, a bhikkhu with good friends abandons the unwholesome and develops the wholesome.”
The Blessed One spoke on this matter. In this regard, it is said:
“The bhikkhu who has good friends,
who is |agreeable::deferential, polite, obedient [sappatissa]| and respectful;
Acting according to the advice of friends,
with |full awareness::attentiveness, clear and full comprehension [sampajañña]| and |mindfulness::remembering to be present with continuous effort, observing the body in and of itself, felt experience in and of itself, mind in and of itself, mental qualities in and of themselves [patissata, sati]|;
Gradually attains,
the |wearing away of all fetters::wearing away of all the chains, slow destruction of all the bonds [sabbasaṃyojanakkhaya]|.”
This matter too was spoken by the Blessed One, as I have heard.