The second perek of Massekhet Hagiga opens with a discussion of certain topics in the Torah that should not be taught in public settings. For example, arayot – forbidden sexual relationships – should not be taught to more than two students at a time. Ma’aseh bereishit – the secrets of creation – are limited to a single student, while ma’aseh merkava – the secrets of the supernatural – cannot be taught even to a single student, unless he is a scholar who has the ability to understand on his own. According to the Gemara, the concern in all of these cases is that one student may begin to ask the teacher questions and during the distraction the others may begin discussions that will keep them from focusing on the continued lecture. In these issues, if the students rule incorrectly, the repercussions can be severe.
On a superficial level, the Mishna turns to this topic as a natural continuation to the discussion that appeared in the last perek. There we learned (see the Mishna on 10a) that some halakhot are clearly written and developed in the Torah, others are mentioned succinctly, and some are barely hinted at and are left to the Sages. Similarly we find entire topics that the Sages felt needed to remain “hidden” from public view and only taught within a small circle of the initiated. In his Zekher LaHagiga, Rav Mordechai Zvi Reinhold suggests a further connection with Massekhet Hagiga. He argues that the obligation to travel to Jerusalem and to approach God in His Temple is a mitzva of deep and great significance. Far from being taken lightly, the pilgrim approaching the mikdash needs to be encouraged to appreciate that this trip is not a simple excursion to Jerusalem, but a journey to a higher realm of existence, one that is beyond the ken of the average person. The difficulty here is that even as the significance of the journey should be appreciated by all, the concepts are so complicated that great care must be taken in presenting those ideas to the masses.