בראשית IN THE BEGINNING — Rabbi Isaac said: The Torah which is the Law book of Israel should have commenced with the verse (Exodus 12:2) “This month shall be unto you the first of the months” which is the first commandment given to Israel. What is the reason, then, that it commences with the account of the Creation? Because of the thought expressed in the text (Psalms 111:6) “He declared to His people the strength of His works (i.e. He gave an account of the work of Creation), in order that He might give them the heritage of the nations.” For should the peoples of the world say to Israel, “You are robbers, because you took by force the lands of the seven nations of Canaan”, Israel may reply to them, “All the earth belongs to the Holy One, blessed be He; He created it and gave it to whom He pleased. When He willed He gave it to them, and when He willed He took it from them and gave it to us” (Yalkut Shimoni on Torah 187).
It was necessary for the mishna to mention the goats sacrificed on the New Moons. It could enter your mind to say that since the term appointed time is not written with regard to them, these offerings do not override Shabbat or ritual impurity as do other communal offerings during their appointed times. Therefore, it teaches us that even the New Moon is called a mo'ed, a holiday.
When the men came to take their wives' gold earrings for the golden calf, the women refused to hand them over. They told their husbands, "We will not obey you and help you make an abomination that has no power or salvation." God rewarded them in this world [for this refusal] by granting them a greater degree of observance on Rosh Chodesh. And God rewards them in the World to Come by giving them the power of constant renewal which characterizes Rosh Chodesh.
(Book of our Heritage, Eliyahu Ki Tov, pg. 222)

