Repetition in Bamidbar

Question

In Bamidbar (1,18) it says:

וְאֵ֨ת כָּל־הָעֵדָ֜ה הִקְהִ֗ילוּ בְּאֶחָד֙ לַחֹ֣דֶשׁ הַשֵּׁנִ֔י וַיִּתְיַֽלְד֥וּ עַל־מִשְׁפְּחֹתָ֖ם לְבֵ֣ית אֲבֹתָ֑ם בְּמִסְפַּ֣ר שֵׁמ֗וֹת מִבֶּ֨ן עֶשְׂרִ֥ים שָׁנָ֛ה וָמַ֖עְלָה לְגֻלְגְּלֹתָֽם׃

Translation (sefaria):

and on the first day of the second month they convoked the whole community, who were registered by the clans of their ancestral houses—the names of those aged twenty years and over being listed head by head.

The pesukim proceed to say the numbers of each tribe, it starts with:

וַיִּהְי֤וּ בְנֵֽי־רְאוּבֵן֙ בְּכֹ֣ר יִשְׂרָאֵ֔ל תּוֹלְדֹתָ֥ם לְמִשְׁפְּחֹתָ֖ם לְבֵ֣ית אֲבֹתָ֑ם בְּמִסְפַּ֤ר שֵׁמוֹת֙ לְגֻלְגְּלֹתָ֔ם כָּל־זָכָ֗ר מִבֶּ֨ן עֶשְׂרִ֤ים שָׁנָה֙ וָמַ֔עְלָה כֹּ֖ל יֹצֵ֥א צָבָֽא׃

Translation:

They totaled as follows: The descendants of Reuben, Israel’s first-born, the registration of the clans of their ancestral house, as listed by name, head by head, all males aged twenty years and over, all who were able to bear arms.

The pesukim repeat the words "לְמִשְׁפְּחֹתָ֖ם לְבֵ֣ית אֲבֹתָ֑ם בְּמִסְפַּ֤ר שֵׁמוֹת֙ לְגֻלְגְּלֹתָ֔ם כָּל־זָכָ֗ר מִבֶּ֨ן עֶשְׂרִ֤ים שָׁנָה֙ וָמַ֔עְלָה כֹּ֖ל יֹצֵ֥א צָבָֽא" for every tribe.

Why do the pesukim repeat these words?

Answer 1

A nice question, and one that sort of pops-out every time you read this Parasha...

First of all I'd like to point out that your question is inaccurate, there are several modifications in the sentence throughout the tribes: לְגֻלְגְּלֹתָם appears only in the sections of Reuven and Shimon, but is ommited in all other tribes. There are many other changes too, e.g. only for Shimon it says "פְּקֻדָיו", another one is "בְּמִסְפַּר שֵׁמוֹת" which appears in only 4 tribes in Ktiv Male, while in all the others in Ktiv Haser, and so forth, and each of those, even suble changes, is a source for many Parshanuyos. But since you did not ask about the differences, I will not bring those Mefarshim here.

Yet, as you stated, parts of the sentence at large are repeated and some Mefarshim do refer to parts of the repetitions: Rabbi Moshe Alshich says that the repetition of "לְבֵית אֲבֹתָם" comes to show that not only those over the age of 20 had Yichus, but also the younger ones. Or Hachaim says that the repetition of "כָּל יֹצֵא צָבָא" comes to show that all were worthy of serving in the army. Taame Dekra talks about בְּמִסְפַּר שֵׁמוֹת that repeats because of the blessing that they all needed (and adds that the Ktiv Male was for the tribes that needs an extended blessings since they were the ones who resided in Ever HaYarden HaMizrachi which lacked Eretz Yisrael's powers, and Shimon's tribe because of his Pe'or sin)