Shabbos Hagadol: A Special Pass-over
The Gemara in Ta’anis says, “mi’shenichnas Adar marbim b’simcha.” Rashi explains: These are times of nisim (miracles), and this applies to both the months of Adar and Nisan, the times of Purim and Pesach. We learn from here that the simcha we have from the miracles in Adar extends through the month of Nisan as well!
