Which Mitzvah of the 613 Mitzvohs, do we try to refrain from doing the entire month of Iyar?

?

The Rema (Even Hoezer 126 :2^nd6 or 7 in new prints ) writes, “we try to refrain from writing

Gittin, the entire month of Iyar.”

The reason behind it, is, there is a Machlokes How to spell Iyar (1 Yud or 2).  If there is

a danger of Igun then we do write it with 2 Yuds.

R, Akiva Eiger zt”l writes in the Hagohos “The Nachlas Shiva quotes a Yalkut

אברהם יצחק יעקב רחל  The Roshei Tavais spell Iyar (2 Yuds) and that is the סוד המרכבה .”

The possible explanation for the first part is, The Gemoro Rosh Hashana 11a says

Chodesh Ziv is the month of Iyar. The reason it is called Ziv , the Avos were born in

Nissan. The month of Ziv (Iyar) all the Avos were born already. (see Rashi)

The סוד המרכבה, I will not reveal for two reasons a) אין דורשין- ובמרכבה באחד (Chagiga P2 M1)

b) I have no clue what  סוד המרכבה is. *

*once you have reason b), then a) is not necessary