To take the latter question
first, there is general agreement among commentators that the plural better sacrifices is not a precise but a
generic plural, corresponding or accommodated to the plural “these rites” in
the first clause of the verse: the inferior sacrifices of the levitical system
called, speaking generally, for better sacrifices. To be specific, however,
they were superseded not by many sacrifices but by one, namely, the unique and fully adequate self-offering of the
incarnate Son on the cross of Calvary (as our author repeatedly insists—see
7:27; 9:12, 14; 10:10, 12, 14, so that he is not open to the charge of
imprecision). His is the “one sacrifice for sins for ever” (10:12 KJV). Hence
it is described here as better: it
accomplishes once and for all that complete and eternal redemption which the
imperfect sacrifices of the former system never could accomplish. (Philip
Edgcumbe Hughes, A Commentary on the
Epistle to the Hebrews [The New International Commentary on the Old and New
Testament; Grand Rapids, Mich.: Eerdmans, 1977], 379)
