Gal.
3:13): "Christ hath redeemed us from the curse of the law, being made
a curse for us." Now He is said to be a curse for us inasmuch as He
suffered upon the tree, as stated above (Q. 46, A. 4). Therefore He
did redeem us by His Passion.

_I answer that,_ Man was held captive on account of sin in two ways:
first of all, by the bondage of sin, because (John 8:34): "Whosoever
committeth sin is the servant of sin"; and (2 Pet. 2:19): "By whom a
man is overcome, of the same also he is the slave." Since, then, the
devil had overcome man by inducing him to sin, man was subject to the
devil's bondage. Secondly, as to the debt of punishment, to the
payment of which man was held fast by God's justice: and this, too,
is a kind of bondage, since it savors of bondage for a man to suffer
what he does not wish, just as it is the free man's condition to
apply himself to what he wills.

Since, then, Christ's Passion was a sufficient and a superabundant
atonement for the sin and the debt of the human race, it was as a
price at the cost of which we were freed from both obligations. For
the atonement by which one satisfies for self or another is called
the price, by which he ransoms himself or someone else from sin and
its penalty, according to Dan. 4:24: "Redeem thou thy sins with
alms." Now Christ made satisfaction, not by giving money or anything
of the sort, but by bestowing what was of greatest
price--Himself--for us. And therefore Christ's Passion is called our
redemption.

Reply Obj. 1: Man is said to belong to God in two ways. First of all,
in so far as he comes under God's power: in which way he never ceased
to belong to God; according to Dan. 4:22: "The Most High ruleth over
the kingdom of men, and giveth it to whomsoever he will." Secondly,
by being united to Him in charity, according to Rom. 8:9: "If any man
have not the Spirit of Christ, he is none of His." In the first way,
then, man never ceased to belong to God, but in the second way he did
cease because of sin. And therefore in so far as he was delivered
from sin by the satisfaction of Christ's Passion, he is said to be
redeemed by the Passion of Christ.

Reply Obj. 2: Man by sinning became the bondsman both of God and of
the devil. Through guilt he had offended God, and put himself under
the devil by consenting to him; consequently he did not become God's
servant on account of his guilt, but rather, by withdrawing from
God's service, he, by God's just permission