Let your friend's honor be as dear to you as your own/ Let your neighbour's honour be as dear to you as your own!
Honor your friend with the same consideration that you would give to your own honor. The honor of your friend must be as precious in your eyes as your own honor.
("They said three things: Rabbi Eliezer says: Let your friend's honor be as dear to you as your own, and do not be quick to anger" - Avot 2:10)
Translation
Expression (Hebrew)
יְהִי כְּבוֹד חֲבֵרְךָ חָבִיב עָלֶיךָ כְּשֶׁלְּךָ
Definition (Hebrew)
כַּבֵּד אֶת חֲבֵרְךָ בְּאוֹתָהּ חֲשִׁיבוּת שֶׁאַתָּה מְיַחֵס לִכְבוֹדְךָ שֶׁלְּךָ. כְּבוֹד זוֹלְךָ צָרִיךְ לִהְיוֹת יָקָר בְּעֵינֶיךָ כְּמוֹ כְּבוֹדְךָ.
("הֵם אָמְרוּ שְׁלֹשָׁה שְׁלֹשָׁה: דְּבָרִים רַבִּי אֱלִיעֶזֶר אוֹמֵר יְהִי כְּבוֹד חֲבֵרְךָ חָבִיב עָלֶיךָ כְּשֶׁלָּךְ וְאַל תְּהִי נוֹחַ לִכְעֹס"- אָבוֹת ב ט-י )