נָ֣סוּ וְאֵין־רֹדֵ֣ף רָשָׁ֑ע וְ֝צַדִּיקִ֗ים כִּכְפִ֥יר יִבְטָֽח׃
דער רָשע לױפֿט װען קײנער יאָגט ניט, אָבער די צדיקים זײַנען זיכער װי אַ יונגער לײב.
Ibn Ezra
Whoever eats [plural] will suffer [singular] Each one of the people who eat it, as in “The righteous [plural] are secure [singular] like a lion” [Proverbs 28:1] [cf. comment on Deuteronomy 7:10].
Rabbeinu Bahya
מברכיך ברוך “the ones who bless you, may they be blessed.” Although Bileam combines plural and singular in this verse, we encounter something similar in both Genesis 49,22 and Proverbs 28,1.
Ibn Ezra
He repays His enemies [plural] every one of his enemies (as in, “the righteous [plural] are secure [singular] like a lion” [Proverbs 28: 1] [cf. comment on Leviticus 19: 8])