Comentário sobre Números 26:2

לבית אבתם [TAKE THE SUM OF THE CONGREGATION] ACCORDING TO THEIR FATHERS’ HOUSE — after their fathers’ tribes shall they reckon their descent, and not after their mothers’ (Bava Batra 109b).

מבן עשרים שנה ומעלה מבית אבותם, “from twenty years and up according to their respective fathers’ house.” When enumerating the tribe of Reuven, the Torah here omits the addition למשפחותם, ”according to their families,” which we had found in the previous census (Numbers 1,2). The reason is that in the interval of almost 40 years some intermarriage with the members of Korach’s family had occurred, as a result of which such members of Korach’s expanded family perished with him. [This is not surprising, as the discontented Reuvenites had felt sympathy for Korach’s rebellion and intermarriage between them was based on common interests. Ed.] (The author refers the reader to his commentary on Numbers 1,18 where he dealt with this at greater length)

שאו את ראש, “take a census.” Our sages (Tanchuma Pinchas 4) explained the reason for this census at this time by means of a parable. A shepherd whose flock had been attacked by wolves which had killed many of his sheep counted the surviving sheep in order to assess his losses. Furthermore, seeing that Moses had counted the people shortly after the Exodus, now that he was close to the end of his career he wanted to prove that he had the same number of people at his command to hand over to his successor.