The halacha states that Klal Yisroel counts the months according to the lunar cycle, while the nations of the world count according to solar cycle. The source for this is in the Mechilta on this wee’s Parsha. The passuk says, “This month is for you,” referring to the mitzvah of declaring the new month based on the new moon. The Mechilta comments that the passuk is exact when it says, “for you,” because the rest of the world does not count according to the new moon, but rather on the cycle of the sun.

Rabbi Aharon Dovid Singer
Rosh Kollel, NMB Kollel
305-972-6508