For the Catholic there is what is known as the Deposit of Faith which is considered that which cannot be altered, or omitted by the Church. Although our understanding of the contents may be expanded and explained in an organic growth of the Church’s understanding, the substance itself must never be changed. This Deposit of Faith is all that the Church was given by Christ and His Apostles as a deposit to be presented to Him at His Parousia (the second coming): so that we may not be guilty of the stern warning of Christ, “But yet the Son of man, when he cometh, shall he find, think you, faith on earth?” (Luke 18:8)
Indeed the Church is responsible for keeping this faith incorrupt whether by word (Holy Scripture) or by Holy Tradition. She is accountable to God for passing this faith on, spotless and undefiled.
I was thinking of Paul’s verse in I Corinthians 9:24, “Know you not that they that run in the race, all run indeed, but one receiveth the prize? ” It seems to me to paint a picture that may help non-Catholics understand the necessity of this mission to carry forth this Deposit of Faith completely intact.
A Modern Parable might then be constructed as follows:
If there were a great relay Race that were to be run by mankind where a Baton would be passed from father to son until the Judge decided the Race was done, we would expect that the rules would be fair and that a handicap would be given to those in need to compensate for their disadvantage.
At the start of the Race mankind would let the Apostles and those who were converted to the faith at Pentecost carry the Baton until their death. They would all receive the Holy Spirit which could then be passed on to their sons in faith via the Baton. It is a standard Baton with a miraculous property such that it can be multiplied and handed on to many more people than those who start the race and it remains exactly the same no matter how many times this reoccurs. This Baton is measured and weighed for its content before the Race and thereby the Judge can examine the Baton once again at the finish.
Some over the ages will drop their Batons or quit the Race. Others will stoop to pick up something that may look somewhat similar to the Baton but is much lighter in weight, with some of the content gone missing. That is obviously an unfair advantage to those who traded the original for a lighter replica.
If we are to be judged by the Judge at the end of this Great Race, how will He handicap those who have been handed a lighter replica as opposed to those who have succeeded in passing on the Original? Though we do not know the mind of the Judge, it is suspected that if rewards are being given as trophies to those who finish the Race, the more Glorious Awards might go to those who present the Baton intact.
So it is with the Church. Our aim is to pass on the Baton from generation to generation completely intact with nothing added and nothing removed. It might be a somewhat relevant analogy up to a point.