Talmud for Pirkei Avot 1:6
יְהוֹשֻׁעַ בֶּן פְּרַחְיָה וְנִתַּאי הָאַרְבֵּלִי קִבְּלוּ מֵהֶם. יְהוֹשֻׁעַ בֶּן פְּרַחְיָה אוֹמֵר, עֲשֵׂה לְךָ רַב, וּקְנֵה לְךָ חָבֵר, וֶהֱוֵי דָן אֶת כָּל הָאָדָם לְכַף זְכוּת:
Yehoshuah ben Prachya and Nitai Ha'arbeli received it from them. Yehoshua ben Prachya says: Make a teacher for yourself. [Rambam explains: Even if he is not fit to be your teacher, still make him your teacher, and do not learn by yourself. And I have heard: "Make a teacher for yourself" that you learn from constantly, and do not learn today from one and tomorrow from another. And even though they said (Avodah Zarah 19a): "If one learns Torah from only one master, he never sees a sign of blessing," they have already explained: That is true of svara (sharpening in dialectics after the "substance" has been acquired), it being beneficial for one to hear the svara of the many; but in gemara (acquiring the "substance" itself), one master is preferable, to avoid differences in formulations of the same (oral learnings)], and acquire a friend for yourself, [even if it is very costly for you to do so, and you must spend much to acquire his love. But it cannot be stated "Acquire a teacher for yourself," a teacher being obliged to teach gratis], and judge each man in the scales of merit. [This is so when the act is in the balance, it not being discernible from his deeds whether he is righteous or wicked and he performs a deed which permits of judging him in the scales of merit or in those of guilt; it is the way of lovingkindness to judge him in the scales of merit. But if one is confirmed in evil, it is permitted to judge him in the scales of guilt, their having stated only (Shabbath 97a): "If one suspects the innocent he is smitten in his body," implying that if he suspects the wicked he is not smitten.]
Avot D'Rabbi Natan
Avot D'Rabbi Natan
They asked Rabban Yohanan ben Zakkai: A wise person who fears sin – what is he like? He replied: Like a craftsman with his tool in hand. Then they asked: A wise person who does not fear sin – what is he like? He replied: Like a craftsman who does not have his tool in hand. Then they asked: A person who fears sin but is not wise – what is he like? He replied: Like someone who does not know the craft, but has a tool in his hand.
Rabbi Elazar ben Azariah would say: If there is no Torah, there is no common decency. [If there is no common decency, there is no Torah.] He would also say: A person who has done good deeds, and has learned a lot of Torah – what is he like? Like a tree that stands near the water, whose branches are small, but whose roots are so strong that even if the four winds of the world all came and blew at it, it could not be moved from its place, as it says (Psalms 1:3), “He is like a tree planted by (streams of) water.” But a person who has not done good deeds and studies Torah, what is he like? Like a tree that stands in the desert, with small branches and small roots, and when a wind comes and blows at it, it uproots it and flips it over on its top, as it says (Jeremiah 17:6), “You will be like a bush in the desert.”
Rabban Gamliel would say: Make for yourself a teacher. Acquire for yourself a friend. A teacher for wisdom and a friend to study with. Remove yourself from all doubts, and do not get used to tithing by estimation.