Sangha and Noble Friendship
To follow up with our earlier conversation about Sangha, I've come across a great passage from the Samyutta-Nikaya. The Buddha is discussing the role of noble friendship and it's primary importance to overcoming hindrances as well as cultivating the other areas of the eightfold path.
The entire holy life, Ananda, is noble friendship, noble companionship, noble association. Of a monk, Ananda, who has a noble friend, a noble companion, a noble associate, it is to be expected that he will cultivate and practice the Noble Eightfold Path.
— SN 45:2