You may be sure that this refractory nature, which demands much toil, has been implanted in us. There are obstacles in our path; so let us fight, and call to our assistance some helpers. “Whom,” you say, “shall I call upon? Shall it be this man or that?” There is another choice also open to you; you may go to the ancients; for they have the time to help you. We can get assistance not only from the living, but from those of the past. Let us choose, however, from among the living, not men who pour forth their words with the greatest glibness, turning out commonplaces and holding. as it were, their own little private exhibitions, – not these, I say, but men who teach us by their lives, men who tell us what we ought to do and then prove it by practice, who show us what we should avoid, and then are never caught doing that which they have ordered us to avoid.

~ Seneca from, http://www.lettersfromastoic.net/letter-52-on-choosing-our-teachers/

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