וַיֵּ֨לְכ֜וּ בְּנֵ֨י מָכִ֧יר בֶּן־מְנַשֶּׁ֛ה גִּלְעָ֖דָה וַֽיִּלְכְּדֻ֑הָ וַיּ֖וֹרֶשׁ אֶת־הָאֱמֹרִ֥י אֲשֶׁר־בָּֽהּ׃
므낫세의 아들 마길의 자손은 가서 길르앗을 쳐서 취하고 거기 있는 아모리인을 쫓아내매
Rashi
ויורש — Understand this as the Targum does “AND HE DROVE OUT”, for the expression ריש is used in two different meanings, in the sense of ירושה (the Kal), “inheriting”, and in the sense of הורשה (the Hiphil) which denotes driving away and expelling (see Rashi on Numbers 14:24).
Ralbag
The first benefit is to highlight the great diligence of Moses in performing the commandments of the Almighty, even though he knew that afterwards he would gather his people for war. He did not hesitate to take swift action and exact revenge according to what was possible.