What prompted the Nesi'im to bring the Korbanos in addition to their initial donation?
Rashi: After donating the wagons and the oxen to transport the Mishkan, they had an urge to donate Korbanos 1 with which to inaugurate the Mizbe'ach. 2
Ramban (in Pesukim 2-5): They actually brought the wagons and oxen together with the Korbanos. simultaneously.
What is the meaning of "Chanukas ha'Mizbe'ach"?
Rashi (in Lech L'cha, 14:14): It means the inauguration 1 of the Mizbe'ach.
Rashi (Ibid.): Initiating a vessel into the function that it is destined to serve.
What are the implications of "Vayakrivu ha'Nesi'im es Korbanam Lifnei ha'Mizbe'ach"?
Rashi: They brought their gift of animals in front of the Mishkan - but Moshe did not accept it, until Hashem instructed him to do so.
Ramban: Refer to 7:3:4:2**.
Why was Moshe hesitant to bring the Korbanos that the Nesi'im donated?
Ramban (in Pasuk 13): The concept of inaugurating the Mizbe'ach came from the Nesi'im. Consequently, since Hashem had not instructed Moshe to do so, he hesitated until Hashem accepted the Nesi'im's proposal. 1
Torah Temimah: He was not sure in which order to bring them 2 and whether to bring them all on one day or on consecutive days; so he waited for instructions.
Oznayim la'Torah #1: Because he maintained that if Hashem had not commanded him to inaugurate the Mishkan and the Mizbe'ach, then He did not want them to be inaugurated.
Oznayim la'Torah #2: Having announced "Ish ve'Ishah Al Ya'asu Od Melachah li'Terumas ha'Kodesh", he did not deem it correct to accept any more gifts before asking permission to do so. 3
Refer to 7:3:7:1.
What is the difference between the first half of the Pasuk and the second half?
Seforno: The first half of the Pasuk is referring to declaring the animals Hekdesh; the second half, to bringing them in front of the Mizbe'ach.
