Here it may be queried, whether the Lord Jesus Christ underwent the idem, the very self-same punishment that we should have undergone? or only the tantundem, that which did amount, and was equivalent thereunto? That in different respects, both may be affirmed. The punishment which Christ endured, if it be considered in its substance, kind, or nature, so ‘twas the same with that the sinner himself should have undergone, but if it be considered with respect to certain circumstances, adjuncts, or accidents, which attend that punishment, (as inflicted upon the sinner) so ‘twas but equivalent and not the same. The punishment due to the sinner was death, the curse of the law (upon the breach of the first covenant), now this Christ underwent, “For he was made a curse for us,” Gal. iii. 13. The adjuncts attending this death were the eternity of it, desperation going along with it, &c., these Christ was freed from (the dignity of his person supplying the former, the sanctity of his person, securing him against the latter), therefore in reference unto these (and to some other things already mentioned) it was but the tantundem, not the idem. But suppose there had been nothing of sameness, nothing beyond equivalency in what Christ suffered, yet that was enough, for it was not required that Christ should suffer every kind of curse, which is the effect of sin, but in the general accursed death. Look as in his fulfilling of the law for us, it was not necessary that he should perform every holy duty that the laws requires, for he could not perform that obedience which magistrates, or married persons are bound to: it’s enough that there was a fulfilling of it in the general for us. So here it is not necessary that Jesus Christ should undergo in every respect the same punishment which the offender himself was liable unto, but if he shall undergo so much as may satisfy the law’s threatenings, and vindicate the law-giver in his truth, justice, and righteous government, that was enough. Now that was unquestionably done by Christ.
Thomas Brooks, A Golden Key to Open Hidden Treasures (Printed for Robert Smith, at the Sign of the Gilt-Bible, near the head of the Salt-mercat, 1763), 148-149.