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׃
가령 사람이 그 이웃과 함께 벌목하러 삼림에 들어가서 손에 도끼를 들고 벌목하려고 찍을 때에 도끼가 자루에서 빠져 그 이웃을 맞춰 그로 죽게함 같은 것이라 이런 사람은 그 성읍 중 하나로 도피하여 생명을 보존할 것이니라
Rashi
ונשל This is an expression denoting casting away, and throwing to a distance, and similar is, (Deuteronomy 19:5) “and the iron flies off" (ונשל).
Rashbam
ונשל, he threw. If one uproots, or separates anything its position where it was firmly attached is described in such terms. Compare Deuteronomy 28,40 כי ישל זיתיך, “for your olives will drop off.” Compare also Deut. 19,5 ונשל הברזל מן העץ, “the iron (axe) will fall off the handle.”
Ramban
WHEN THE ETERNAL THY G-D SHALL CUT OFF THE NATIONS etc. 2. THOU SHALT SEPARATE THREE CITIES FOR THEE. This also is an explanatory commandment, since He has already commanded thereon,239Exodus 21:13. and now he went on to explain the ordinances thereof, saying and dwell in their cities, and in their houses,240Verse 1. teaching that they are not obligated [to set aside the cities of refuge] until after taking possession of the Land and dwelling in it. And so Joshua did.241Joshua, Chapter 20. He also added here, Thou shalt prepare thee the way,242Verse 3. meaning that the roads leading thereto should be direct [without being unnecessarily circumflex], and that [signs reading] “Refuge, Refuge” be set up at the crossroads. So also he added and thou shalt divide the territory of thy Land into three parts242Verse 3. [meaning, that the cities shall be equidistant from the frontier and from each other]. And he also went on to teach us [the rules of] the matter of “error” [which require the unintentional murderer to seek refuge] as he said, And when a man goeth into the forest with his neighbor etc.243Verse 5. Our Rabbis have based many more interpretations on this section.