Matthew Poole and continuators on Deuteronomy 33:9

9 Who said unto his father, and to his mother, I have not seen him , neither did he acknowledge his brethren, nor knew his own children: for they have observed thy word, and kept thy covenant .

(i. e.) I have no respect unto them, for so knowledge is oft used, as Iob 9. 21. Prov. 12. 10, 11. 1 Thess. 5. 12. The sense is, who followed God and his command fully, and executed the judgment enjoyned by God without any respect of persons, Exod. 32. 26, 27. This seems better than to refer it, either to their not mourning for their next kindred, for that was allowed to all but the High-Priest in case of the Death of Father or Mother, and that was onely a ceremonial rite and no matter of great commendation; or to their impartiality in executing the judgments committed to them, Deuteronomy 17. 9. of which they had as yet given no considerable proof.

(i. e.) When the rest broke their covenant with God by that soul sin of Idolatry with the calf, that Tribe kept themselves more pure from that infection, and adhered to God and his Worship and Service, as appears from Exod. 32. 26, 28. Compare Mal. 2. 6, 7.

Marginal references: Mal. 2. 5.