Musar su Genesi 48:9

Now to a more detailed examination of the subject of betrothal and wedding. The sanctification of the moon is an expression of Israel's sanctification. This is alluded to in the words: החודש הזה לכם, "This month belongs to you." The Jewish Court has been given authority by G–d to declare when the New Moon officially commences, i.e. whether the month just concluded will have twenty-nine or thirty days. The Court similarly enjoys the authority to declare an extra month when this is necessary to ensure that Passover falls in spring, etc. (Rosh Hashanah 22). This is a mystical aspect of the betrothal. It is written here "This month is yours,” and it is written in Genesis 48,9: אשר נתן לי אלוקים בזה, "which the Lord had given me here." On this latter verse Rashi comments that Joseph showed his father the documents testifying to his traditional betrothal and marriage. The sanctity of the Sabbath testifies to the existence of G–d as the Creator. The sanctity of the Sabbath belongs to G–d in His capacity as the Ineffable Name and is eternal. All our sages are agreed that on the festival of Shavuot (which commemorates the giving of the Torah) the element of לכם is essential [just as in the verse announcing that the New Moon is given over to the Jewish people, Ed.], since G–d spoke to us directly on that occasion.