The Tipiṭaka in Three Languages

Nāhantaekadhaṁmapeyyāla

Suttapiṭaka · Saṁyuttanikāya · Mahāvaggasaṁyutta · Vol. 19 · Section 165

[165] The setting is Sāvatthī. Bhikkhus, I do not see even one other thing by which the unarisen Noble Eightfold Path (ariya aṭṭhaṅgika magga) arises, or the arisen Noble Eightfold Path goes to fulfillment by development, so much as this: good friendship (kalyāṇamittatā). Bhikkhus, for a bhikkhu who has a good friend, it is to be expected that he will develop the Noble Eightfold Path, that he will cultivate the Noble Eightfold Path.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 5 other places