Reply Obj. 1: Suffering, as such, is caused by an outward principle: but inasmuch as one bears it willingly, it has an inward principle.
Reply Obj. 2: From the beginning of His conception Christ merited our eternal salvation; but on our side there were some obstacles, whereby we were hindered from securing the effect of His preceding merits: consequently, in order to remove such hindrances, "it was necessary for Christ to suffer," as stated above (Q. 46, A. 3).
Reply Obj. 3: Christ's Passion has a special effect, which His preceding merits did not possess, not on account of greater charity, but because of the nature of the work, which was suitable for such an effect, as is clear from the arguments brought forward above all the fittingness of Christ's Passion (Q. 46, AA, 3, 4). _______________________
SECOND ARTICLE [III, Q. 48, Art. 2]
Whether Christ's Passion Brought About Our Salvation by Way of
Atonement?
Objection 1: It would seem that Christ's Passion did not bring about our salvation by way of atonement. For it seems that to make the atonement devolves on him who commits the sin; as is clear in the other parts of penance, because he who has done the wrong must grieve over it and confess it. But Christ never sinned, according to 1 Pet. 2:22: "Who did no sin." Therefore He made no atonement by His personal suffering.
Obj. 2: Further, no atonement is made to another by committing a graver offense. But in Christ's Passion the gravest of all offenses was perpetrated, because those who slew Him sinned most grievously, as stated above (Q. 47, A. 6). Consequently it seems that atonement could not be made to God by Christ's Passion.
Obj. 3: Further, atonement implies equality with the trespass, since it is an act of justice. But Christ's Passion does not appear equal to all the sins of the human race, because Christ did not suffer in His Godhead, but in His flesh, according to 1 Pet. 4:1: "Christ therefore having suffered in the flesh." Now the soul, which is the subject of sin, is of greater account than the flesh. Therefore Christ did not atone for our sins by His Passion.
On the contrary, It is written (Ps. 68:5) in Christ's person: "Then did I pay that which I took not away." But he has not paid who has not fully atoned. Therefore it appears that Christ by His suffering has fully atoned for our sins.
I answer that, He properly atones for an offense who offers something which the offended one loves equally, or even more than he detested the offense. But by suffering out of love and obedience, Christ gave more to God than was required to compensate for the offense of the whole human race. First of all, because of the exceeding charity from which He suffered; secondly, on account of the dignity of His life which He laid down in atonement, for it was the life of one who was God and man; thirdly, on account of the extent of the Passion, and the greatness of the grief endured, as stated above (Q. 46, A. 6). And therefore Christ's Passion was not only a sufficient but a superabundant atonement for the sins of the human race; according to 1 John 2:2: "He is the propitiation for our sins: and not for ours only, but also for those of the whole world."