Eight causes of discernment:
1. There is the case where a monk lives in apprenticeship to the Teacher or to a respectable comrade in the holy life in whom he has established a strong sense of conscience, fear of blame, love, and respect.
2. As he lives in apprenticeship under the Teacher or under a respectable comrade in the holy life in whom he has established a strong sense of conscience, fear of blame, love, and respect, he approaches him at the appropriate times to ask and question him: “What, venerable sir, is the meaning of this statement?” He reveals what is hidden, makes plain what is obscure, and dispels perplexity in many kinds of perplexing things.
3. Having heard the Dhamma, he achieves a twofold seclusion: seclusion in body and seclusion in mind.
4. He is virtuous. He dwells restrained in accordance with the Patimokkha (code of conduct for monks and nuns), consummate in his behavior and sphere of activity. He trains himself, having undertaken the training rules, seeing danger in the slightest faults.
5. He has heard much, has retained what he has heard, has stored what he has heard. Whatever teachings are admirable in the beginning, admirable in the middle, admirable in the end, that; in their meaning and expression; proclaim the holy life that is entirely complete and pure: those he has listened to often, retained, discussed, accumulated, examined with his mind, & well-penetrated in terms of his views.
6. He keeps his persistence aroused for abandoning unskillful mental qualities and for taking on skillful mental qualities. He is steadfast, solid in his effort, not shirking his duties with regard to skillful mental qualities.
7. When he is in the midst of the Sangha he doesn't talk on and on about a variety of things. Either he speaks Dhamma himself or he invites another to do so, and he feels no disdain for noble silence.
8. He remains focused on arising and passing away with regard to the five aggregates.
(from Anguttara Nikaya 8.2)