And they set out from Hor Hahar through the way of the Sea of Reeds. That is that the group stopped studying the Talmud, which is called Hor HaHar. Why is it called Hor HaHar? Because from there comes teaching [hora'ah] to the world, as "I have written to instruct them [lehorotam]" (Exodus 24:12) - and this is the Oral Torah [Mishnah, Talmud and Midrash].
(במדבר כא) וַיִּסְעוּ מֵהֹר הָהָר דֶּרֶךְ יַם סוּף. הָא אִתְעָרוּ חַבְרַיָיא, דִּנְטָלוֹ מִלְּאוֹלָפָא תַּלְמוּדָא, דְּאִקְרֵי הֹר הָהָר. אַמַּאי אִקְרֵי הֹר הָהָר, בְּגִין דִּמְתַמָּן נָפֵיק הוֹרָאָה לְעָלְמָא. דִּכְתִיב (שמות כד) אֲשֶׁר כָּתַבְתִּי לְהוֹרֹתָ"ם, וְדָא אִיהוּ תּוֹרָה שֶׁבְּעַל פֶּה.
And they set out from Hor Hahar through the way of the Sea of Reeds. That is that the group stopped studying the Talmud, which is called Hor HaHar. Why is it called Hor HaHar? Because from there comes teaching [hora'ah] to the world, as "I have written to instruct them [lehorotam]" (Exodus 24:12) - and this is the Oral Torah [Mishnah, Talmud and Midrash].