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Why is the new-moon offering different, in that the phrase ‘a sin offering unto the Lord’ (Numbers 28:15) is used in connection with it [whereas ordinarily the phrase ‘a sin offering’ is used without the additional ‘unto the Lord’]? Because the Holy One, blessed be He said, ‘This goat will be an atonement for My diminishing the moon [and causing creation to be incomplete]. (Tractate Shavuot 9A)