Hebrews 9:20

Saying, this is the blood of the testament,.... The first testament or covenant; this proves what the apostle had asserted in Hebrews 9:18 that it was dedicated with blood, or confirmed by it; compare with this Matthew 26:28

which God hath enjoined unto you; the people of Israel, to observe, and which they promised to do; see Exodus 24:7.