The Chatas, sin-offering, which Aharon HaKohen brought, was personal. It atoned for his participation in the chet ha’eigal, Golden Calf debacle. Why was it necessary for Aharon to offer up his korban prior to offering up the communal offering? Horav Eliyahu Meir Bloch, zl, derives from here that, prior to teaching others, one must first and foremost show that he himself is free of any such taint. When one seeks to convey his hashkafos, perspectives/outlook on life (based upon the Torah) to others, he must first be an exemplar of his teaching. K’shot atzmecha v’achar kach k’shot acheirim, “Beautify yourself first and (only) then attempt to beautify others.” Simply, this Chazal (Sanhedrin 18a) teaches that one should reflect on his own actions and self-evaluate prior to having the presumption to criticize others.
Horav S. R. Hirsch, zl, explains that the first time the word k’shot is used, it is related to the Aramaic word kushta, which means “truth.” In other words, Chazal are being frank with us. Be truthful with yourself – do not delude yourself that you are perfect – before you have the temerity to rebuke others. First of all, it is improper. Second, it will be ineffective. No one wants to be criticized by a chameleon who expediently changes to please others to further his own goals. Thus, Aharon publicly addressed his own “failing” before he sought forgiveness from the nation.
Horav Naftali Amsterdam, zl, was one of the primary students of Horav Yisrael Salanter, zl. His erudition and righteousness notwithstanding, he made every attempt to conceal his greatness and his role in his saintly Rebbe’s mussar movement. Out of fear that his service to Hashem would become a source of false pride, he was self-effacing even in his private life. He obstinately refused to accept any service from others, and he vehemently demurred from entering the field of rabbanus. He earned his meager livelihood as a baker, whose products his wife sold in their little bakery. Sadly, his returns were less than satisfactory. When his daughter reached marriageable age, he was unable to provide for her dowry. In the end, he took a rabbinic position, followed by becoming a dayan in Petersburg – a position he held until he earned enough money to cover his payables. He then returned to full-time learning.
Rav Naftali neither had to teach his students mussar, ethical character development, from a book, nor lecture to them from a lectern, because he himself was a living volume of mussar. He embodied the highest ideals of mussar.
It is related that one week the holy Chafetz Chaim cancelled his weekly shmuess, ethical discourse. At the appointed time, he ascended to the lectern and said, “Kinderlach, my children, today I am unable to offer words of mussar. I can neither arouse your emotions nor inspire you, because this week I received copies of the Mishnah Berurah (his magnum opus), and I was compelled to spend long hours reviewing and editing each volume for errors. I would hate to sell a volume that had mistakes. This would be tantamount to stealing. I cannot demand diligence in Torah study when I myself have been lax in my commitment.”