[55.]There is a wide difference between the flower of youth and the maturity of age; yet they who were once young are still the same now that they have become old, insomuch that though the stature and outward form of the individual are changed, yet his nature is one and the same, his person is one and the same. An infant’s limbs are small, a young man’s large, yet the infant and the young man are the same. Men when full grown have the same number of joints that they had when children; and if there be any to which maturer age has given birth these were already present in embryo, so that nothing new is produced in them when old which was not already latent in them when children. This, then, is undoubtedly the true and legitimate rule of progress, this the established and most beautiful order of growth, that mature age ever develops in the man those parts and forms which the wisdom of the Creator had already framed beforehand in the infant. Whereas, if the human form were changed into some shape belonging to another kind, or at any rate, if the number of its limbs were increased or diminished, the result would be that the whole body would become either a wreck or a monster, or, at the least, would be impaired and enfeebled.
[56.] In like manner, it behooves Christian doctrine to follow the same laws of progress, so as to be consolidated by years, enlarged by time, refined by age, and yet, withal, to continue uncorrupt and unadulterate, complete and perfect in all the measurement of its parts, and, so to speak, in all its proper members and senses, admitting no change, no waste of its distinctive property, no variation in its limits.
[57.] For example: Our forefathers in the old time sowed wheat in the Church’s field. It would be most unmeet and iniquitous if we, their descendants, instead of the genuine truth of grain, should reap the counterfeit error of tares. This rather should be the result—there should be no discrepancy between the first and the last. From doctrine which was sown as wheat, we should reap, in the increase, doctrine of the same kind— wheat also; so that when in process of time any of the original seed is developed, and now flourishes under cultivation, no change may ensue in the character of the plant. There may supervene shape, form, variation in outward appearance, but the nature of each kind must remain the same. God forbid that those rose-beds of Catholic interpretation should be converted into thorns and thistles. God forbid that in that spiritual paradise from plants of cinnamon and balsam, darnel and wolfsbane should of a sudden shoot forth.
Therefore, whatever has been sown by the fidelity of the Fathers in this husbandry of God’s Church, the same ought to be cultivated and taken care of by the industry of their children, the same ought to flourish and ripen, the same ought to advance and go forward to perfection. For it is right that those ancient doctrines of heavenly philosophy should, as time goes on, be cared for, smoothed, polished; but not that they should be changed, not that they should be maimed, not that they should be mutilated. They may receive proof, illustration, definiteness; but they must retain withal their completeness, their integrity, their characteristic properties.
[59.] But the Church of Christ, the careful and watchful guardian of the doctrines deposited in her charge, never changes anything in them, never diminishes, never adds, does not cut off what is necessary, does not add what is superfluous, does not lose her own, does not appropriate what is another’s, but while dealing faithfully and judiciously with ancient doctrine, keeps this one object carefully in view—if there be anything which antiquity has left shapeless and rudimentary, to fashion and polish it, if anything already reduced to shape and developed, to consolidate and strengthen it, if any already ratified and defined, to keep and guard it.