וַֽיִּתְּנֵ֛הוּ יְהוָ֥ה אֱלֹהֵ֖ינוּ לְפָנֵ֑ינוּ וַנַּ֥ךְ אֹת֛וֹ וְאֶת־בנו [בָּנָ֖יו] וְאֶת־כָּל־עַמּֽוֹ׃
At ibinigay siya sa harap namin ng Walang-Hanggan na aming Diyos, at ginapi namin siya, ang kanyang mga anak, at ang kanyang buong bayan.
Rashi
ואת בנו [AND WE SMOTE HIM] AND HIS SONS — It is written בנו, "his son" (although read as בניו "his sons"), for he had a son who was as mighty as himself (Midrash Tanchuma, Chukat 25).
Ibn Ezra
The word we defeated is missing the initial nun of the triliteral root.
Siftei Chakhamim
It (בנו) is written, etc. Since בנו lacks the letter yud, it [means “his son” and] implies that Sichon only had one son. Yet, since both syllables are vocalized with a kamatz, it [means “his sons” and] implies that he had many sons. Rather the word בנו indicates that Sichon had one son who was clearly recognizable as his son, for he was as mighty as his father. Therefore, it is written בנו (his son), without a yud. And this verse is informing us that he was killed just as all his other sons were killed.