"Just as the city accepts, so too its boundary accepts." And they raised a contradiction: "And he shall dwell in it, but not in its boundary." Abaye said: This is not difficult. Here it is referring to the city's acceptance, and here it is referring to the boundary's acceptance. And you can derive from it that they do not make a field a boundary, and a boundary a field; they do not make a city a boundary, and a boundary a city. Rav Sheshet said: This is only necessary for leniencies. "Until the death of the High Priest," Rabbi Meir says: A murderer shortens the days of a person's life, while a High Priest extends the days of a person's life. It is not just that someone who shortens the days of a person's life should face judgment before someone who extends the days of a person's life. Rabbi says: A murderer defiles the land and removes the Divine presence, while a High Priest causes the Divine presence to dwell in the land. This is not a proper judgment, etc. And if he leaves, he leaves. Rabbi Elazar ben Azariah says: If the measure of punishment is mild and he takes even one step, he becomes liable for his life. By analogy, we learn that a greater measure of kindness applies. The Sages teach: "And if he leaves, he leaves." I would only know that this applies to intentional acts. From where do I derive that it also applies to accidental acts? The verse states: "And if he leaves, he leaves" — regardless. And it was taught in a Baraita: For an intentional act, he is killed, but for an accidental act, he is exiled. This is not difficult: Here, when the Torah speaks in the language of human beings, and here, when the Torah does not speak in the language of human beings. Abaye said: It is logical to conclude that when the Torah speaks in the language of human beings, the outcome should not be more severe than the beginning. Just as the beginning, in the case of an intentional act, results in being killed and exiled for an accidental act, so too, the outcome, in the case of an intentional act, should result in being killed and exiled for an accidental act.
Cities of Refuge and Their Expanding Boundaries
Yalkut Shimoni on Torah 788:8
עַד מוֹת הַכֹּהֵן הַגָּדֹל. רַבִּי מֵאִיר אוֹמֵר רוֹצֵחַ מְקַצֵּר יָמָיו שֶׁל אָדָם וְכֹהֵן גָּדוֹל מַאֲרִיךְ יָמָיו שֶׁל אָדָם, אֵין בַּדִּין שֶׁיְּהֵא מִי שֶׁמְּקַצֵּר יָמָיו שֶׁל אָדָם לִפְנֵי מִי שֶׁמַּאֲרִיךְ יָמָיו שֶׁל אָדָם. רַבִּי אוֹמֵר רוֹצֵחַ מְטַמֵּא אֶת הָאָרֶץ וּמְסַלֵּק אֶת הַשְּׁכִינָה, וְכֹהֵן גָּדוֹל גּוֹרֵם לַשְּׁכִינָה שֶׁתִּשְׁרָה בָּאָרֶץ, אֵינוֹ דִין וְכוּ'. וְאִם יָצֹא יֵצֵא, אָמַר רַבִּי אֶלְעָזָר בֶּן עֲזַרְיָה, אִם מִדַּת פֻּרְעָנוּת מֻעֶטֶת הַפּוֹסֵעַ פְּסִיעָה אַחַת הֲרֵי הוּא מִתְחַיֵּב בְּנַפְשׁוֹ, קַל וָחֹמֶר לְמִדַּת טוֹבָה מְרֻבָּה.