Exodus 24:8
7 He took the Book of the Covenant and read it aloud to the people, and they said, “We are willing to do and obey all that the Lord has spoken.” 8 So Moses took the blood and splashed it on the people and said, “This is the blood of the covenant that the Lord has made with you in accordance with all these words.” 9 Moses and Aaron, Nadab and Abihu, and the seventy elders of Israel went up, 10 and they saw the God of Israel. Under his feet there was something like a pavement made of sapphire, clear like the sky itself.
Hebrews 9:20
19 For when Moses had spoken every command to all the people according to the law, he took the blood of calves and goats with water and scarlet wool and hyssop and sprinkled both the book itself and all the people, 20 and said, “This is the blood of the covenant that God has commanded you to keep.” 21 And both the tabernacle and all the utensils of worship he likewise sprinkled with blood.
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