.

Obj. 2: Further, that which existed in the Old Law had not to be
instituted in the New. Now there was Penance in the old Law wherefore
the Lord complains (Jer. 8:6) saying: "There is none that doth
penance for his sin, saying: What have I done?" Therefore Penance
should not have been instituted in the New Law.

Obj. 3: Further, Penance comes after Baptism, since it is a second
plank, as stated above (A. 6). Now it seems that our Lord instituted
Penance before Baptism, because we read that at the beginning of His
preaching He said (Matt. 4:17): "Do penance, for the kingdom of
heaven is at hand." Therefore this sacrament was not suitably
instituted in the New Law.

Obj. 4: Further, the sacraments of the New Law were instituted by
Christ, by Whose power they work, as stated above (Q. 62, A. 5; Q.
64, A. 1). But Christ does not seem to have instituted this
sacrament, since He made no use of it, as of the other sacraments
which He instituted. Therefore this sacrament was unsuitably
instituted in the New Law.

_On the contrary,_ our Lord said (Luke 24:46, 47): "It behooved
Christ to suffer, and to rise again from the dead the third day: and
that penance and remission of sins should be preached in His name
unto all nations."

_I answer that,_ As stated above (A. 1, ad 1, ad 2), in this
sacrament the acts of the penitent are as matter, while the part
taken by the priest, who works as Christ's minister, is the formal
and completive element of the sacrament. Now in the other sacraments
the matter pre-exists, being provided by nature, as water, or by art,
as bread: but that such and such a matter be employed for a sacrament
requires to be decided by the institution; while the sacrament
derives its form and power entirely from the institution of Christ,
from Whose Passion the power of the sacraments proceeds.

Accordingly the matter of this sacrament pre-exists, being provided
by nature; since it is by a natural principle of reason that man is
moved to repent of the evil he has done: yet it is due to Divine
institution that man does penance in this or that way. Wherefore at
the outset of His preaching, our Lord admonished men, not only to
repent, but also to "do penance," thus pointing to the particular
manner of actions required for this sacrament. As to the part to be
taken by the ministers, this was fixed by our Lord when He said to
Peter (Matt. 16:19): "To thee will I give the keys of the kingdom of
heaven," etc.; b