Degel Machaneh Ephraim On Rosh Chodesh Nisan
Excerpt from Degel Machaneh Ephraim, Parshas Bo:
Why is the month of Nisan called the Chodesh ha-Aviv (the month of Spring)?
We can explain this by way of the verse in Mishlei 8:15 "Bi Melachim Yimlochu" - through Me kings shall rule. There are 12 mazalos (zodiac signs) which correspond to the 12 months. These in turn have 12 corresponding combinations of the spelling of the four letter name of Hashem (YH"VH) which rules over each month.
The zodiac constellations influence the decisions and actions of the kings and rulers that are decided by way of these letter combinations. This is alluded to in the first word in the verse in Mishlei , "Bi" that is spelled with a yud and bet and equals the number 12, corresponding to the number of letter combinations of the Divine four letter Name. This verse can then be read as: "Bi Melachim Yimlochu - through the 12 combinations of the Divine Name, kings shall rule."
Therefore the month of Aviv which is Nisan, is the head of the year. It is the Rosh haShana for kings. This is because the combination of the four letter Divine Name is in order on the month of Nisan (YH"VH). It is the "Av" (father) of all other possible combinations which are all "born" from that initial order.
I heard from my grandfather (the holy Baal Shem Tov) that he once said on Rosh Chodesh Nisan to the famous Maggid from Tortshin,
"Now at this moment we must pray, because the first of Nisan is the Rosh haShana for kings, and all the "sarim" (angelic leaders) are appointed as to how well they shall rule over the world, and just now they appointed angelic leaders which are not good and extremely detrimental to our cause, therefore now is the time to pray."
This is what I heard from his holy mouth.
Translation by Rabbi Tal Zwecker