Avos 1:6 עֲשֵׂה לְךָ רַב (notes)

"Make for yourself a (Torah) mentor": Rambam explained, “Even though he is not fit to be your teacher, make him into your teacher and do not learn on your own.” And I heard, “'Make for yourself a teacher,' [meaning] that he should take on one teacher from which always to learn – and not learn from one today and from another one tomorrow." And even though they stated in tractate Avodah Zara 19, “One who learns from [only] one teacher will not see a sign of blessing;” they have already explained and said, “this applies to reasoning” - as it is good for him to hear the reasoning of the many - “but with concern to [memorization of traditional teachings], it is better from one teacher, so that [the student's] elocution not be damaged."

"acquire for yourself a friend": And even if you need to acquire him for a large sum and to spend money upon him in order to acquire his love. But with a mentor, it is not applicable to say, "Acquire for yourself a mentor," as a [teacher of Torah] must teach for free.

"and judge every person as meritorious": when the matter is hanging in the balance and there is no way to decide it in this way or that way. For example, a man from whose actions we do not know if he is righteous or wicked, who preforms an act that is possible to judge favorably and possible to judge unfavorably, it is pious to judge him favorably. But it is permissible to judge a man who is established to be evil unfavorably. As they only stated (Shabbat 97), “one who suspects righteous people is afflicted on his body” - [and so] it is implied [from this] that one who suspects evildoers is not afflicted.

"acquire for yourself a friend": A person needs three things from a good friend. One is for words of Torah, as it stated (Taanit 7a), "I have learned much from my teachers and more from my friends than from my teachers." And the second is for commandments. As even if his friend is not more pious than he and there are times that he does what is not in order. [Yet it is only] when he derives pleasure from something that he does the sin, but it is not his desire and his will that his friend do it - as he derives no enjoyment from this. And it is like they said (Kiddushin 63b), "And a man will not sin if it is not for himself." It comes out that both of them will repent, each one according to the word of his friend. And the third is regarding advice that he can take, that he be 'one who arouses (a counselor) for help' in all of his affairs and to take good counsel from him and to be his confidant. Since he is his ally, he will not reveal [his secrets] to others so as not to confound his plan - and not even to those that appear to him to be friends; for is the appearance of love evident on their faces? And about this Shlomo, peace be upon him, stated (Proverbs 15:22), "Plans are foiled for want of counsel, but they succeed through many advisers." And that which he said, "acquire for yourself a friend" with an expression of [acquisition] (euphemism) is [to say] that if he does not find him for free, he should acquire him with his money and expend his assets in order to get to a good friend; or that he should acquire him with words of appeasement and with a soft way of talking. And [so] he should not be exacting about his words and he should tolerate the words of his mouth; even when he says something against him, he should not return a response. As without this, he will not keep [the friendship], since the opinions [of people] are different. And sometimes he will seek something, [but] his friend who is like himself will say, "See, I do not [consider] this to be fit." And if he doesn't [listen to his friend] (he will certainly pass him up), the [friendship] will unravel. And this is what Shlomo, peace be upon him, stated (Proverbs 17:9), "He who seeks love covers errors, but he who harps on a matter alienates a leader." He meant to say, one who covers when his friend errs, seeks love - as through this, their love is preserved, as he tolerates his errors. But if he harps about the matter with his friend, he speaks against him and repeats it and says, "See what this one said; what he said about me, he 'alienates the leader' - he(certainly) alienates his leader from him, meaning to say, his friend.

Many days passed, and Shu’a’s daughter, the wife of Yehudah died. Yehudah sought consolation, and went up to his sheep-shearers—he and his friend, Chirah the Adullamite—to Timnah.