"...and they stood at the lowermost part of the mount” (Exodus 19:17). Rabbi Avdimi bar Ḥama bar Ḥasa said: the Jewish people actually stood beneath the mountain, and the verse teaches that the Holy One, Blessed be He, overturned the mountain above the Jews like a tub, and said to them: If you accept the Torah, excellent, and if not, there will be your burial. Rav Aḥa bar Ya’akov said: From here there is a substantial caveat to the obligation to fulfill the Torah. The Jewish people can claim that they were coerced into accepting the Torah, and it is therefore not binding. Rava said: Even so, they again accepted it willingly in the time of Ahasuerus, as it is written: “The Jews ordained, and took upon them, and upon their seed, and upon all such as joined themselves unto them” (Esther 9:27), and he taught: The Jews ordained what they had already taken upon themselves through coercion at Sinai.
”ויתיצבו“– נצפפו. מלמד שהיו ישראל מתיראין מפני הזיקין מפני הזועות מפני הרעמים מפני הברקים הבאים.
”בתחתית ההר“– מלמד שנתלש ההר ממקומו, וקרבו ועמדו תחת ההר, שנאמר: ”ותקרבון ותעמדון תחת ההר.“ עליהם מפורש בקבלה ”יונתי בחגוי הסלע בסתר המדרגה הראיני את מראיך…“
The great scholar of Talmudic and medieval Jewish thought, Ephraim Urbach (1912-1991), observed that R. Avdimi’s exegesis appears to rework a tannaitic comment on the same verse (Mek. R. Ishmael ba-Chodesh 3 [Horovitz-Rabin ed., 214]):
“And they took their places.” Pressed together. It teaches that they were scared on account of the flashing and trembling and thunder, on account of the approaching lightning.
“The foot of the mountain.” It teaches that the mountain was plucked from its place, and they approached and stood under the mountain, as it is said, “and you approached and stood under the mountain” (Deut 4:11). Of them it is explicated in the tradition (Song 2:14): “My dove in the clefts of the rock, in the covert of the cliff, show me your appearance, etc.”
In this earlier account, God positions the mountain over Israel not to threaten them, but to protect them from the thunder and lightning and to allay their anxiety.
Tzvi Novick, "Standing Under Sinai: On the Origins of a Coerced Covenant" TheTorah.com (2015). https://thetorah.com/article/standing-under-sinai-on-the-origins-of-a-coerced-covenant