ציטירנדיקער פּירוש אויף במדבר 23:18

לכהנו לי, “to serve Me as priests;” the letter ו at the end of the word: לכהנו, is superfluous, just as in Psalms 104 11, or in Numbers 24,3, or in Numbers 23,18. (Compare Ibn Ezra’s short commentary)

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).

מדו, as in Numbers 23,18 בנו צפור, [in both instances the letter ו at the end is something extraneous. Ed.] It again occurs in that mode in Numbers 24,3. Basically the word מד refers to some kind of garment, especially work oriented or vocation oriented, as in Samuel I 4,12 where the expression ומדיו קרועים, refer to a “torn uniform.”