indirect
grows out of · why a new one
Jeremiah's promise of a covenant written on hearts answers the failure the calf exposed.
direct
points forward to · the new covenant
Jesus does not invent the phrase. 'This cup is the new covenant in my blood' announces that Jeremiah's promise is now being enacted.
direct
points forward to · quoted in full
Hebrews quotes Jeremiah 31 at length and draws the conclusion that calling one covenant new makes the first obsolete.