which we obtain through His death, according to Heb.
9:11: "Christ is [Vulg.: 'being come'] a high-priest of the good
things to come"; for which reason the priesthood of Christ is said to
be eternal. Now this consummation of Christ's sacrifice was
foreshadowed in this, that the high-priest of the Old Law, once a
year, entered into the Holy of Holies with the blood of a he-goat and
a calf, as laid down, Lev. 16:11, and yet he offered up the he-goat
and calf not within the Holy of Holies, but without. In like manner
Christ entered into the Holy of Holies--that is, into heaven--and
prepared the way for us, that we might enter by the virtue of His
blood, which He shed for us on earth.

Reply Obj. 1: The Saints who will be in heaven will not need any
further expiation by the priesthood of Christ, but having expiated,
they will need consummation through Christ Himself, on Whom their
glory depends, as is written (Apoc. 21:23): "The glory of God hath
enlightened it"--that is, the city of the Saints--"and the Lamb is
the lamp thereof."

Reply Obj. 2: Although Christ's passion and death are not to be
repeated, yet the virtue of that Victim endures for ever, for, as it
is written (Heb. 10:14), "by one oblation He hath perfected for ever
them that are sanctified."

Wherefore the reply to the third objection is clear.

As to the unity of this sacrifice, it was foreshadowed in the Law in
that, once a year, the high-priest of the Law entered into the
Holies, with a solemn oblation of blood, as set down, Lev. 16:11. But
the figure fell short of the reality in this, that the victim had not
an everlasting virtue, for which reason those sacrifices were renewed
every year.
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SIXTH ARTICLE [III, Q. 22, Art. 6]

Whether the Priesthood of Christ Was According to the Order of
Melchisedech?

Objection 1: It would seem that Christ's priesthood was not according
to the order of Melchisedech. For Christ is the fountain-head of the
entire priesthood, as being the principal priest. Now that which is
principal is not secondary in regard to others, but others are
secondary in its regard. Therefore Christ should not be called a
priest according to the order of Melchisedech.

Obj. 2: Further, the priesthood of the Old Law was more akin to
Christ's priesthood than was the priesthood that existed before the
Law. But the nearer the sacraments were to Christ, the more clearly
they signified Him; as is clear from what we h