Mahānāradakassapajātaka

Suttapiṭaka · Khuddakanikāya · Jātaka (2) · Vol. 28 · Section 862

[862] "Whomever a man attends upon, O king — whether a good man (santa) or a bad (asanta), whether virtuous or devoid of virtue — into that very one's power he goes. Whatever sort of man he makes his friend, whatever sort he frequents, even such a one does he become, for such is dwelling together. The one who associates defiles the one with whom he associates; the one touched, touching another, defiles him in turn, as a poisoned arrow defiles the quiver yet unsmeared. For fear of contamination, the wise man (dhīra) should never take the wicked for friends. The man who wraps putrid fish in blades of kusa grass finds the kusa blades too wafting putrid: such is consorting with fools (bāla). The man who wraps tagara incense in a palāsa leaf finds the leaves too wafting fragrant: such is consorting with the wise. Therefore, knowing that his own ripening (sampāka) will be even as the leaf-wrapper's, the wise man (paṇḍita) should not consort with the bad; he should consort with the good: the bad lead one to hell (niraya), the good bring one to a happy destination (sugati)."

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.