City of God

It is certain that Christ rose in the same bodily stature in which He died, and that it is wrong to say that, when the general resurrection shall have arrived, His body shall, for the sake of equalling the tallest, assume proportions which it had not when He appeared to the disciples in the figure with which they were familiar. But if we say that even the bodies of taller men are to be reduced to the size of the Lord's body, there will be a great loss in many bodies, though He promised that, not a hair of their head should perish.

It remains, therefore, that we conclude that every man shall receive his own size which he had in youth, though he died an old man, or which he would have had, supposing he died before his prime. As for what the apostle said of the measure of the age of the fullness of Christ, we must either understand him to refer to something else, viz., to the fact that the measure of Christ will be completed when all the members among the Christian communities are added to the Head; or if we are to refer it to the resurrection of the body, the meaning is that all shall rise neither beyond nor under youth, but in that vigor and age to which we know that Christ had arrived.

For even the world's wisest men have fixed the bloom of youth at about the age of thirty; and when this period has been passed, the man begins to decline towards the defective and duller period of old age. And therefore the apostle did not speak of the measure of the body, nor of the measure of the stature, but of “the measure of the age of the fullness of Christ.”