Exodus 19:12
10 The Lord said to Moses, “Go to the people and sanctify them today and tomorrow, and make them wash their clothes 11 and be ready for the third day, for on the third day the Lord will come down on Mount Sinai in the sight of all the people. 12 You must set boundaries for the people all around, saying, ‘Take heed to yourselves not to go up on the mountain nor touch its edge. Whoever touches the mountain will surely be put to death! 13 No hand will touch him—but he will surely be stoned or shot through, whether a beast or a human being; he must not live.’ When the ram’s horn sounds a long blast they may go up on the mountain.” 14 Then Moses went down from the mountain to the people and sanctified the people, and they washed their clothes.
Hebrews 12:20
18 For you have not come to something that can be touched, to a burning fire and darkness and gloom and a whirlwind 19 and the blast of a trumpet and a voice uttering words such that those who heard begged to hear no more. 20 For they could not bear what was commanded: “If even an animal touches the mountain, it must be stoned.” 21 In fact, the scene was so terrifying that Moses said, “I shudder with fear.” 22 But you have come to Mount Zion, the city of the living God, the heavenly Jerusalem, and to myriads of angels, to the assembly
Notes and References
"... There are only two citations, or quotations, of Exodus in Hebrews that scholars agree upon: Exodus 25:40 in Hebrews 8:5 and of Exodus 24:8 in 9:20. In Hebrews 12:20 we find what I describe as a condensed paraphrase of Exodus 19:12-13, where a longer portion of text is condensed with close verbal similarity preserved and, for that reason, there is no debate as to whether Hebrews 12:20 references Exodus 19:12-13. There are many instances, however, in which Hebrews alludes to Exodus and, in those cases, Hays’ criteria are most relevant. Some of the most significant allusions I (and others) identify, for instance, include the “word spoken through angels” in 2:2 (angels at Sinai), the wilderness generation (thematic allusions) and the promise of rest (Exodus 33:14) in Hebrews 3-4. The reference to God’s rest after creation in relation to the Sabbath command in 4:4 may allude to Genesis but it may also (or instead) allude to the Decalogue in Exodus and/or Exodus 31:17. Hebrews 5:1, 4 allude to the call of Aaron from among the people to be a priest (Exodus 28:1) and Hebrews dialogues with the concept of Aarons’ perpetual priestly line throughout Hebrews 5-7, as well. A detailed description of the wilderness tabernacle in Heb 9 alludes very specifically to Exodus115 and references to both covenant and atoning rituals in Hebrews can easily be understood as alluding to Exodus and/or Leviticus ..."
Moore, Scott Ronald A Conviction of Texts Not Seen: Perceiving Exodus as the Generative Text of Hebrews (pp. 69-70) University of Denver, 2017