Musar for Pirkei Avot 2:9
אָמַר לָהֶם, צְאוּ וּרְאוּ אֵיזוֹהִי דֶרֶךְ יְשָׁרָה שֶׁיִּדְבַּק בָּהּ הָאָדָם. רַבִּי אֱלִיעֶזֶר אוֹמֵר, עַיִן טוֹבָה. רַבִּי יְהוֹשֻׁעַ אוֹמֵר, חָבֵר טוֹב. רַבִּי יוֹסֵי אוֹמֵר, שָׁכֵן טוֹב. רַבִּי שִׁמְעוֹן אוֹמֵר, הָרוֹאֶה אֶת הַנּוֹלָד. רַבִּי אֶלְעָזָר אוֹמֵר, לֵב טוֹב. אָמַר לָהֶם, רוֹאֶה אֲנִי אֶת דִּבְרֵי אֶלְעָזָר בֶּן עֲרָךְ מִדִּבְרֵיכֶם, שֶׁבִּכְלָל דְּבָרָיו דִּבְרֵיכֶם. אָמַר לָהֶם צְאוּ וּרְאוּ אֵיזוֹהִי דֶרֶךְ רָעָה שֶׁיִּתְרַחֵק מִמֶּנָּה הָאָדָם. רַבִּי אֱלִיעֶזֶר אוֹמֵר, עַיִן רָעָה. רַבִּי יְהוֹשֻׁעַ אוֹמֵר, חָבֵר רָע. רַבִּי יוֹסֵי אוֹמֵר, שָׁכֵן רָע. רַבִּי שִׁמְעוֹן אוֹמֵר, הַלֹּוֶה וְאֵינוֹ מְשַׁלֵּם. אֶחָד הַלֹּוֶה מִן הָאָדָם, כְּלֹוֶה מִן הַמָּקוֹם בָּרוּךְ הוּא, שֶׁנֶּאֱמַר (תהלים לז) לֹוֶה רָשָׁע וְלֹא יְשַׁלֵּם, וְצַדִּיק חוֹנֵן וְנוֹתֵן. רַבִּי אֶלְעָזָר אוֹמֵר, לֵב רָע. אָמַר לָהֶם, רוֹאֶה אֲנִי אֶת דִּבְרֵי אֶלְעָזָר בֶּן עֲרָךְ מִדִּבְרֵיכֶם, שֶׁבִּכְלָל דְּבָרָיו דִּבְרֵיכֶם:
He (R. Yochanan ben Zakkai) said to them: Go out and see which is the just way to which a man should cleave. R. Eliezer says: A good eye, [being satisfied with what one has, not desiring superfluities, and not being envious when he sees that his friends have more than he.] R. Yehoshua says: A good friend, [who reproves him if he sees him doing something improper.] R. Yossi says: A good neighbor, [who is there for him both day and night (whereas a good friend is not there for him at all times.)] R. Shimon says: One who foresees what is to come, and, in consequence, weighs the loss of a mitzvah against its reward and the reward of a transgression against its loss (see 2:1)]. R. Elazar says: A good heart. [For the heart activates all of the other faculties and is the source of all deeds. And even though there are distinct limbs for (distinct) activities, it is the heart which is the "awakener" of all. Therefore,] R. Yochanan ben Zakkai said to them: I see the words of R. Elazar ben Arach [to be more cogent than yours], for your words are included in his. He said to them: Go and see which is the wicked way which a man should distance himself from. [He was constrained to ask this and did not understand from their words (above) that the wicked way is the opposite of the good way because the opposite of the good is not necessarily evil. For (for example), the trait of chasiduth (saintliness), doing what is above and beyond the letter of the law, is good; but one who is not a chasid and bases his conduct on the law of the Torah, is not wicked. And it may be said that though satisfaction (with what one has), "a good eye," is a good thing, a desire for superfluities is not "the wicked way," for he hurts no one thereby, and the same for all the middoth. He must, therefore, ask them: "Which is the wicked way which a man must distance himself from?"] R. Eliezer says: A wicked eye. R. Yehoshua says: A bad friend. R. Yossi says: A bad neighbor. R. Shimon says: One who borrows and does not repay. [This is the opposite of foreseeing what is to come. For if he does not repay, he will find no one to lend him and he will languish in hunger. He does not simply say: "One who does not foresee what is to come, for it is possible for such a man not to come to harm by rescuing himself when the contingency arrives)]. Borrowing from a man is like borrowing from the L rd, as it is written (Psalms 37:21): "The wicked one borrows and does not repay, and the Tzaddik is gracious and gives." [The Holy One Blessed be He, who is the tzaddik of the world, is gracious and gives to the lender what this one borrowed from him and did not repay — whence it emerges that the borrower remains indebted to the L rd.] R. Elazar says: A wicked heart. He said to them: I see the words of R. Elazar ben Arach [to be more cogent than yours], for your words are included in his.