וַאֲשֶׁר֩ יָבֹ֨א אֶת־רֵעֵ֥הוּ בַיַּעַר֮ לַחְטֹ֣ב עֵצִים֒ וְנִדְּחָ֨ה יָד֤וֹ בַגַּרְזֶן֙ לִכְרֹ֣ת הָעֵ֔ץ וְנָשַׁ֤ל הַבַּרְזֶל֙ מִן־הָעֵ֔ץ וּמָצָ֥א אֶת־רֵעֵ֖הוּ וָמֵ֑ת ה֗וּא יָנ֛וּס אֶל־אַחַ֥ת הֶעָרִים־הָאֵ֖לֶּה וָחָֽי׃
例如人與鄰舍一同進入樹林砍伐木柴，他揮動斧頭要砍樹，鐵斧頭卻從木柄上脫落，擊中鄰舍，以致鄰舍死了。這人可以逃到這些城中的一座，就得以存活；
Sifra
12) Rabbi says: It is written (Devarim 19:5): "And one who comes with his neighbor in the forest to chop wood, and his hand swing the axe to cut the tree, and the iron slip from the haft and it find his neighbor and he die — he shall flee to one of these cities (or refuge), and he shall live." Scripture ordained the saving of the life of one who unwittingly slew another. Deduce therefrom: The collector of charity, the feeder of the poor, the doer of lovingkindness — how much more so will his life be granted him!
Sifrei Devarim
(Ibid. 4) "one who smites his neighbor": Why is "his neighbor" mentioned three times (in the context of the cities of refuge)? "his neighbor" — to exclude (from the cities of refuge) others (i.e., gentiles); "his neighbor" — to exclude a sojourning convert; "his neighbor" — even "his neighbor," a father (who killed) his son or a son (who killed) his father. (Ibid. 4) "not having hated him": But if he had hated him, he is not exiled. ("not having hated him) mitmol shilshom":
Sifrei Devarim
(Devarim 19:5) "And one who comes with his neighbor in the forest": Just as a forest is a place that the slain and the slayer were permitted to enter, so all such places (are subsumed in the halachah) — to exclude the owner's courtyard, which the slayer had no right to enter.