Commentary for Numbers 24:3

בנו בער — The grammatical form בנו is exactly like that in (Psalms 114:8) “To a spring of (מעינו) water” (see Rashi on Numbers 23:18). But a Midrashic statement is: Both of them (Balak and Balaam) were superior to their fathers, for it states (Numbers 23:18): “Balak — his son was Zippor”, i.e. that his father (Zippor) was his son (his inferior) in respect to royalty, and Balaam was greater than his father in prophecy (because it states here, בלעם בנו בעור i.e. Balaam — his son was Beor): he was, so to speak, a Maneh, son of a Half-Maneh (Sanhedrin 105a, Midrash Tanchuma, Balak 13, cf. Taanit 28b).

SHETHUM HA’AYIN.’ The commentators have not found the root of this word [shethum] anywhere else in Scripture. Onkelos translated it: “who sees well,” as [if to say] “open-eyed,” and in the language of the Sages we find:²⁰⁶Abodah Zarah 69a. “sufficient time sheyishtom and to close it up” — meaning to say: [enough time to open a hole in the barrel of wine] — and to stop it up again. Perhaps the word [shethum] is a composite one [consisting of the two words shethui mah — “whatever is put” before the eye], from the root ‘shithi’ (My setting) these My signs,²⁰⁷Exodus 10:1. Thus, unlike Rashi and R’dak who explain the word shethum on the basis of the root shatham found in the Mishnah, Ramban explains it on the basis of Biblical language. [and here it means] that Balaam is a person [of whom one can use the phrase] “whatever is put” [before him] — because he understands everything that he puts his eye upon.

וישא משלו, "He began his parable, etc." Why were these two words necessary? We also need to know why he had to say: "says Bileam, etc." Who did not know that Bileam was speaking? Furthermore, why did Bileam have to tel us once more who his father was? Besides, why did he have to give details about identifying marks on his body? What did he mean when he said: "who hears the words of G'd?" If he meant to boast that he was privy to communications from G'd, why had he waited so long to do this?