Talmud for Pirkei Avot 4:15
רַבִּי יַנַּאי אוֹמֵר, אֵין בְּיָדֵינוּ לֹא מִשַּׁלְוַת הָרְשָׁעִים וְאַף לֹא מִיִּסּוּרֵי הַצַּדִּיקִים. רַבִּי מַתְיָא בֶן חָרָשׁ אוֹמֵר, הֱוֵי מַקְדִּים בִּשְׁלוֹם כָּל אָדָם. וֶהֱוֵי זָנָב לָאֲרָיוֹת, וְאַל תְּהִי רֹאשׁ לַשּׁוּעָלִים:
R. Yannai says: It is not in our hands [i.e., We do not understand (viz. Yevamoth 105a)] why the wicked are at peace, [why they prosper,] and why the righteous are afflicted. [Or: We do not have in exile either the peace and tranquility that the Holy One Blessed be He is wont to bestow upon the wicked in order to drive them out of the world to come, or the afflictions that are unique to the righteous, the afflictions of love, which do not entail the suspension of Torah study. That is, we are not in the category of the wicked, not having their tranquility, nor have we attained to the category of the righteous; for our afflictions are not those of love, as theirs are. ] R. Matia ben Charash says: Precede every man in greeting, [even a gentile in the marketplace], and be a tail to the lions [i.e., to those who are greater than you], and do not be a head to the foxes [i.e., to those who are lesser than you].