Idra Raba is a cave located in the north of Israel, between Meron and Zephath. Rasbhi took his students to this cave, and there he wrote The Book of Zohar. It is almost impossible to understand how great Rabbi Shimon Bar-Yochai really was. He belongs, as Baal HaSulam puts it, to the highest Inner Light. This is why he had to use Rabbi Abba to put his words into writings. In The Book of Zohar, the Rasbhi tells his students: I am arranging you as follows: Rabbi Abba will write.