What is the significance of seven bulls and seven rams each day?
Rashi: The Torah says (to offer two bulls, one ram and seven lambs each day! The only way I can establish this verse is to teach that there will be seven bulls and seven rams in all during the seven days ? one bull and one ram each day 1 . This teaches that the bulls are not Me'akev each other, and the rams are not Me'akev each other 2 , like it says in Menachos (76b). However, it learned from below "uv'Yom ha'Chodesh Par Ben Bakar Temimim v'Sheshes Kevasim va'Ayil" (46:6). Perhaps also our verse comes to teach this.
Radak: These are in addition to Korbanos of the Chag written in the Torah.
Malbim: "Shiv'as ha'Yamim" teaches that they will offer seven every day!
Granted, we learn that the bulls are not Me'akev each other, for the Torah commanded to offer two each day, and they will offer only one. What is the source that the rams are not Me'akev each other? The Torah commanded to offer only one each day? Perhaps the Hekesh to bulls (our verse mentions both of them) teaches that when the Torah obligates two rams, they are not Me'akev each other. (PF)
Why will he offer a Se'ir Chatas each day?
Rashi: These are goats of the festivals.
Malbim: Also this is for Chinuch.