'Therefore, Adam was created alone… to teach you that whoever saves a single soul, Scripture accounts it as if he had saved an entire world.' Each person contains a world; and just as Adam was singular, every individual has an irreplaceable path.
לְפִיכָךְ נִבְרָא אָדָם יְחִידִי, לְלַמֶּדְךָ שֶׁכׇּל הַמְאַבֵּד נֶפֶשׁ אַחַת מִיִּשְׂרָאֵל, מַעֲלֶה עָלָיו הַכָּתוּב כְּאִילּוּ אִיבֵּד עוֹלָם מָלֵא. וְכׇל הַמְקַיֵּים נֶפֶשׁ אַחַת מִיִּשְׂרָאֵל, מַעֲלֶה עָלָיו הַכָּתוּב כְּאִילּוּ קִיֵּים עוֹלָם מָלֵא. וּלְהַגִּיד גְּדוּלָּתוֹ שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא, שֶׁאָדָם טוֹבֵעַ כַּמָּה מַטְבְּעוֹת בְּחוֹתָם אֶחָד – כּוּלָּן דּוֹמִין זֶה לָזֶה, וּמֶלֶךְ מַלְכֵי הַמְּלָכִים הַקָּדוֹשׁ בָּרוּךְ הוּא טָבַע כׇּל אָדָם בְּחוֹתָמוֹ שֶׁל אָדָם הָרִאשׁוֹן, וְאֵין אֶחָד מֵהֶן דּוֹמֶה לַחֲבֵירוֹ. לְפִיכָךְ כָּל אֶחָד וְאֶחָד חַיָּיב לוֹמַר: בִּשְׁבִילִי נִבְרָא הָעוֹלָם.
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. And this serves to tell of the greatness of the Holy One, Blessed be He, as when a person stamps several coins with one seal, they are all similar to each other. But the supreme King of kings, the Holy One, Blessed be He, stamped all people with the seal of Adam the first man, as all of them are his offspring, and not one of them is similar to another. Therefore, since all humanity descends from one person, each and every person is obligated to say: The world was created for me, as one person can be the source of all humanity, and recognize the significance of his actions.