בַּעֲשׂוֹתְךָ֥ נוֹרָא֖וֹת לֹ֣א נְקַוֶּ֑ה יָרַ֕דְתָּ מִפָּנֶ֖יךָ הָרִ֥ים נָזֹֽלּוּ׃
Als du Wunderbares tatest, was wir nicht erwartet, stiegst du nieder, vor deinem Antlitz erzitterten Berge.
Rashi on Isaiah
When You performed against the Egyptians and against all the adversaries awesome deeds, that we did not hope You would perform all those awesome deeds, for we were unworthy of them.
Rashi on Isaiah
You descended to Mount Sinai, then mountains dripped from before You. In this manner, Dunash son of Labrat explained it.