On the Reasons of the Holy Spirit, Book II

If our sense is thought and memory, so that one thing in the soul is distinct by its properties, the sense or apprehension can be harmed more vehemently, and thus the place of perfection is taken from the other two, since if the sense is corrupted, neither reasoning nor reminiscence is valid. The judgment or reasoning can be depraved while the intellect is healthy, and likewise reminiscence. Assume they are persons; since they are one and the same thing, the sense can order the judgment to suspect anything within itself by the will of the sense and the consent of reminiscence, which will pertain only to the reasoning, not likewise to the apprehension. It was done in that way among the divine persons. For the Son is said to have suffered, not by reason of the divinity, but by reason of the subject consisting of man and God, or having within itself the divinity, the soul, and the body. Just as if we were to say that reasoning is harmed because the middle ventricle of the brain, in which is its seat, is badly affected; for the mind of itself is impassible, as I taught in the first book of the Orbis Concordantia Concordance of the World, against Galen. This same subject, necessarily consisting of two natures, in order to join mercy to justice within Himself, sufficiently refutes the vanity of Cerdo and Apelles, who say that Christ did not have a human nature but feigned everything. It is impossible that the justice of God could have been satisfied by any satisfaction except through the afflictions of the flesh, continued in Him from the hour of birth unto the final breath. It also eludes the vanity of those who say there are two persons in Christ; for one composite would have come in vain for redemption unless the immensity of the divinity had been joined to the fragility of the flesh; for otherwise, if they were not one, Christ would be nothing more than any other man.