וַיָּבֹא־שָׁ֥ם אֶל־הַמְּעָרָ֖ה וַיָּ֣לֶן שָׁ֑ם וְהִנֵּ֤ה דְבַר־יְהוָה֙ אֵלָ֔יו וַיֹּ֣אמֶר ל֔וֹ מַה־לְּךָ֥ פֹ֖ה אֵלִיָּֽהוּ׃
And he came thither unto a cave, and lodged there; and, behold, the word of the LORD came to him, and He said unto him: ‘What doest thou here, Elijah?’
Rashi on I Kings
To the cave. That is the cleft of the rock where Moshe stood.3Shemos 33:22. The cave that Eliyahu entered is “the cleft of the rock” in which Moshe stood while God’s Divine Presence passed.4See Maseches Megillah 19b and Rashi there.