א֡וֹ בִּכְלִ֣י עֵֽץ־יָד֩ אֲשֶׁר־יָמ֨וּת בּ֥וֹ הִכָּ֛הוּ וַיָּמֹ֖ת רֹצֵ֣חַֽ ה֑וּא מ֥וֹת יוּמַ֖ת הָרֹצֵֽחַ׃
或者，如果有人用手中足以致人於死的木器打人，以致那人死了，他就是殺人者；殺人者必須被處死。
Rashi
או בכלי עץ יד OR [IF HE SMITE HIM] WITH A WEAPON OF WOOD IN HIS HAND — Because it has been stated, (Exodus 21:20) “And if a man smite his bondman or his bondwoman with a rod”, one might think that it means whatever size it may be! Therefore it states here of the wooden instrument אשר ימות בה — meaning that it must have a size sufficient to cause death (Sifrei Bamidbar 160:4).