1"Bhikkhus, I do not see even a single thing that so causes unarisen wholesome qualities to arise and arisen unwholesome qualities to decline as good friendship. For one with good friends, unarisen wholesome qualities arise and arisen unwholesome qualities decline." [n.57] On the importance of good friendship (kalyāṇamittatā) in the spiritual life, see SN9.3. See too SN45.2

1"Nāhaṁ, bhikkhave, aññaṁ ekadhammampi samanupassāmi yena anuppannā vā kusalā dhammā uppajjanti uppannā vā akusalā dhammā parihāyanti yathayidaṁ, bhikkhave, kalyāṇamittatā. Kalyāṇamittassa, bhikkhave, anuppannā ceva kusalā dhammā uppajjanti uppannā ca akusalā dhammā parihāyantī"ti.

Paṭhamaṁ.