(א) משֶׁה קִבֵּל תּוֹרָה מִסִּינַי, וּמְסָרָהּ לִיהוֹשֻׁעַ, וִיהוֹשֻׁעַ לִזְקֵנִים, וּזְקֵנִים לִנְבִיאִים, וּנְבִיאִים מְסָרוּהָ לְאַנְשֵׁי כְנֶסֶת הַגְּדוֹלָה. הֵם אָמְרוּ שְׁלשָׁה דְבָרִים, הֱווּ מְתוּנִים בַּדִּין, וְהַעֲמִידוּ תַלְמִידִים הַרְבֵּה, וַעֲשׂוּ סְיָג לַתּוֹרָה:
(1) Moshe received the Torah from Sinai and transmitted it to Yehoshua, and Yehoshua to the Elders, and the Elders to the Prophets, and the Prophets transmitted it to the Men of the Great Assembly. They said three things: Be deliberate in judgment, raise up many disciples and make a fence for the Torah.
Avot is a tractate in Seder Nezikin, the part of the Talmud that focuses on civil and criminal law.
Why is it here in this part since it includes wisdom sayings?
EJ: "The inclusion of Avot within an order that discusses civil law, criminal law and the judiciary process, led Maimonides to conclude that Avot was designed to legitimate the authority of rabbinic magistrates and to complement the legal code with a moral and spiritual guide (cf. Ex. 22:20–23:9)." Another possibility: "[It's placed in this part to be an] epilogue to the Mishnah since Nezikin may have once been the last order in the Mishnah or at least the final order to be studied.
Chain of Transmission: There is continuity in God's message from Sinai to the Rabbis. The Rabbis, then, have authority to teach and apply Jewish law in their generation.
Be deliberate in judgment': Rambam - 'Don't rush to judgment...until they understand [fully the case before them], [perhaps] issues will be revealed that
(ב) שִׁמְעוֹן הַצַּדִּיק הָיָה מִשְּׁיָרֵי כְנֶסֶת הַגְּדוֹלָה. הוּא הָיָה אוֹמֵר, עַל שְׁלשָׁה דְבָרִים הָעוֹלָם עוֹמֵד, עַל הַתּוֹרָה וְעַל הָעֲבוֹדָה וְעַל גְּמִילוּת חֲסָדִים:
(2) Shimon the Righteous was from the remnants of the Great Assembly. He would say, "On three things the world stands: on the Torah, on the service and on acts of lovingkindness."
Rambam - 'With wisdom (Torah), with character attributes (gemilut hasadim), and with sacrifices - [that is] constant [work] of tikkun olam [repairing the world - maintaining fairness and preventing social harm (Noam Zion ,'Maimonides Theory of Judicial Discretion, 7/11/2013 - Hartman Institute)
Acts of Lovingkindness: Rashi - These acts [are one of the three pillars because they apply] whether to the wealthy or to the poor, to the dead and the living, to the body and to one's property - which is not the case with tzedakah
Three pillars make a firm base: 'Triangles are the building blocks of many structures mainly because of their ability to bear large loads without deformation. They are considered the strongest shape because a triangular structure subject to strong forces only collapses due to material fatigue and not to geometric distortion.'
(ו) יְהוֹשֻׁעַ בֶּן פְּרַחְיָה וְנִתַּאי הָאַרְבֵּלִי קִבְּלוּ מֵהֶם. יְהוֹשֻׁעַ בֶּן פְּרַחְיָה אוֹמֵר, עֲשֵׂה לְךָ רַב, וּקְנֵה לְךָ חָבֵר, וֶהֱוֵי דָן אֶת כָּל הָאָדָם לְכַף זְכוּת:
(6) Yehoshua ben Perachiah and Nitai of Arbel received from them. Yehoshua ben Perachia says, "Make for yourself a mentor, acquire for yourself a friend and judge every person as meritorious."
Rambam - 'Make for yourself a mentor - even if he is not worthy of being a Rav to you, allow him to be the Rav until you deliver wisdom to him and you acquire wisdom, for a person's learning on his own is not the same as learning from another, rather - learning from another is more lasting and clear, even if the other person is equal to him in wisdom or less so.
Acquire for yourself a friend - It's important to acquire a friend so that he can help you be more of a mensch (she'yitaknu lo kol inya'nav).
Judge every person as meritorious - If you don't know him, and you see him doing something or hear him saying something, and if you interpret it for good - then he is good, and if you interpret it for evil - then it's evil; rather, interpret his actions/words for good....If he's known to you and does something that appears to be evil, allow that the action may have a good side (tzad efsharut liyoto tov). If an evil person does something that appears good, and there's a slight chance it could be evil, then be guarded about him and do not believe it for good...
(יב) הִלֵּל וְשַׁמַּאי קִבְּלוּ מֵהֶם. הִלֵּל אוֹמֵר, הֱוֵי מִתַּלְמִידָיו שֶׁל אַהֲרֹן, אוֹהֵב שָׁלוֹם וְרוֹדֵף שָׁלוֹם, אוֹהֵב אֶת הַבְּרִיּוֹת וּמְקָרְבָן לַתּוֹרָה:
(12) Hillel and Shammai received from them. Hillel says, "Be of the disciples of Aharon, loving peace and pursuing peace, loving the creatures and bringing them closer to Torah."
Rambam - They say that Aaron, may his memory be a blessing, when he sensed, or when they told him of a person who was wicked by nature (adam she'to'cho rah) , and that he has sinned, Aaron would greet him, meet him, and take time to speak with him. The other would say to himself 'Woe is him, if Aaron knew what I plan and what I will do, he would not allow himself to look at me, all the more so to speak with me, and in spite of this I am with him like a person of stature. I will support Aaron's thoughts [about me], do teshuvah, and become one of Aaron's disciples again, and one of those who enjoys from Aaron his advice and resourcefulness.
(יד) הוּא הָיָה אוֹמֵר, אִם אֵין אֲנִי לִי, מִי לִי. וּכְשֶׁאֲנִי לְעַצְמִי, מָה אֲנִי. וְאִם לֹא עַכְשָׁיו, אֵימָתָי:
(14) He [Rabbi Hillel] used to say: If I am not for me, who will be for me? And when I am for myself alone, what am I? And if not now, then when?
Rambam - If I myself do not raise myself up to virtue, who will? [And when I look at] what have I done for good, it's as though he makes himself small in his eyes and says 'What am I'? That is to say, what has come from me?...If I don't acquire virtue now in youth, when will I acquire it?
Tiferet Yisrael - 'If I am not in command of myself and cannot control my delusions of self-importance, how can I expect to discipline myself or convince others to shed their own fantasies?' (Artscroll Pirkei Avot by Rabbi Moshe Lieber)