5. Now, if our having shown above that Christ possessed a rational soul should cause a difficulty to any one, seeing we have frequently proved throughout all our discussions that the nature of souls is capable both of good and evil, the difficulty will be explained in the following way. That the nature, indeed, of His soul was the same as that of all others cannot be doubted, otherwise it could not be called a soul were it not truly one. But since the power of choosing good and evil is within the reach of all, this soul which belonged to Christ elected to love righteousness, so that in proportion to the immensity of its love it clung to it unchangeably and inseparably, so that firmness of purpose, and immensity of affection, and an inextinguishable warmth of love, destroyed all susceptibility (sensum) for alteration and change; and that which formerly depended upon the will was changed by the power of long custom into nature; and so we must believe that there existed in Christ a human and rational soul, without supposing that it had any feeling or possibility of sin.