לפיכך נברא אדם יחידי ללמדך שכל המאבד נפש אחת מישראל מעלה עליו הכתוב כאילו איבד עולם מלא וכל המקיים נפש אחת מישראל מעלה עליו הכתוב כאילו קיים עולם מלא
The court tells the witnesses: Therefore, Adam the first man was created alone, to teach you that with regard to anyone who destroys one soul from the Jewish people, i.e., kills one Jew, the verse ascribes him blame as if he destroyed an entire world, as Adam was one person, from whom the population of an entire world came forth. And conversely, anyone who sustains one soul from the Jewish people, the verse ascribes him credit as if he sustained an entire world.
רַבִּי אֱלִיעֶזֶר אוֹמֵר, יְהִי כְבוֹד חֲבֵרְךָ חָבִיב עָלֶיךָ כְּשֶׁלָּךְ.
Rabbi Eliezer said, "Other people’s dignity should be as precious to you as your own." [AJWS translation]
ואחר שאמר לא תענון לשון רבים אמר אם... תענה, כי כל רואה אדם שהוא מענה יתום ואלמנה ולא יעזרם, גם הוא יחשב מענה
Ibn Ezra, Exodus 22:23
After it says, "Do not oppress" in the plural the language changes to be singular..., for anyone who sees a person oppressing an orphan or a widow and does not come to their aid, they will also be considered oppressors. [AJWS translation]
(טז) הוּא הָיָה אוֹמֵר, לֹא עָלֶיךָ הַמְּלָאכָה לִגְמֹר, וְלֹא אַתָּה בֶן חוֹרִין לִבָּטֵל מִמֶּנָּה.
(16) He [Rabbi Tarfon] used to say: It is not your responsibility to finish the work, but neither are you free to desist from it.