Why does the Torah repeat the word "Nesunim"?
Rashi and R. Bachye #1: Because the Levi'im were designated for Hashem as regards carrying and as regards singing. 1
Seforno: The first "Nesunim" refers to their volunteering to serve Hashem (being Moser Nefesh - R. Bachye) 2 and the second "Nesunim", to the fact that they were given to Hashem from the rest of Yisrael (who became obligated to sustain them with Ma'aser Rishon - Seforno).
Oznayim la'Torah: The Torah divides the Avodas ha'Levi'im into two groups - carrying, which was confined to the era of the desert, and singing, which would apply in the Beis-Hamikdash as well (In that case, it seems that one "Nesunim" pertains to carrying, and the other, to singing and carrying - which also applied in the Beis-Hamikdash).
"Tachas Pitras Kol Rechem". What are the connotations of "Pitras Kol Rechem"?
Rashi, Targum Onkelos and Targum Yonasan: It means 'those who open the womb' (the firstborn [upon whom the Avodah originally rested - Seforno]).


