שְׂא֞וּ אֶת־רֹ֣אשׁ ׀ כָּל־עֲדַ֣ת בְּנֵי־יִשְׂרָאֵ֗ל מִבֶּ֨ן עֶשְׂרִ֥ים שָׁנָ֛ה וָמַ֖עְלָה לְבֵ֣ית אֲבֹתָ֑ם כָּל־יֹצֵ֥א צָבָ֖א בְּיִשְׂרָאֵֽל׃
Bilangin ninyo ang buong kapulungan ng mga anak ni Israel, mula sa dalawampung taong gulang pataas, ayon sa kanilang mga sambahayan ng ama, ang lahat ng may kakayahang humayo sa digmaan sa Israel.
Rashi
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).
Kli Yakar
Take a census, etc. The purpose of this counting now was to inform that even though 24,000 had fallen, nevertheless, 600,000 remained. For a complete multitude is only when there are 600,000, since one can only recite the blessing “Blessed is the One who knows the secrets” when seeing 600,000 (Berakhot 58). Therefore, it comes to inform us that upon their entry to the land, they were a complete multitude.
Tur HaArokh
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)