There are all sorts of proofs for the Catholic Church's claim that she is the One, Holy, Catholic and Apostolic Church, founded by God the Son when on earth, Our Lord Jesus Christ.
Libraries have been written of the subject. Evidence is abundant in Sacred Scripture, of course, in the writings of numerous Fathers, in secular literature of the time (e.g., Pliny) and staring us in the face, literally set in stone, in archeological discoveries, the most cogent right under the High Altar of St Peter's in Rome, thirty feet down – his very bones, beyond reasonable doubt shown to be authentic.
Once a person accepts that there has been public revelation by God, of Himself and of His will, he or she is compelled to accept also that there can be only one true Church, for two obvious reasons: firstly, that God alone has the authority and power to reveal, because of His nature and His essential involvement in all that he has made, no man or woman having such power and authority; and secondly, that His revelation cannot contradict itself.
For instance, some believe there is one Person only in God (metaphysically impossible anyway) while others believe there are three: both cannot be true.
Again, some deny the virginity of Christ's Mother, Mary, while others defend it yet again; some say Christ's Resurrection did not involve His body getting up (as someone said not so long ago: "His bones may still be lying around Palestine ... He rose in the faith of the people") while others died for belief in His bodily Resurrection.
Truth cannot contradict itself. God is not going to reveal one thing to one and its opposite to another: if He did, nothing would make sense, for God would have become a deceiver, and therefore limited, and therefore not God at all.
Nevertheless, history is full of people starting off their own "churches".
Man has no authority or power to found a church, because a church's work is to provide for us the means of having God's life for our salvation, which God alone can provide to teach the truth about God, man, life, death and what happens after it, all of which have to be discovered, having been revealed by God, not invented by man to instruct, in God's name, how we are to live, so that all may share His life of goodness, preventing the alternative of mankind tearing itself apart with its awful antipathies.
The first of note was Cerinthus who claimed each had the Holy Spirit revealing to him personally, and so there was no need for the Church. And then, of similar mind, came the endless procession from Arius to the founder of the Church of Jesus the Magic Carpenter, and all between.
Well, we are still going, despite all the persecutions from enemies without and the weird inventions of those within who believed they could make up their own Jesus.
A story of survival
Those of my vintage (ordained 1962) had the great privilege of sitting at the feet of that incomparable Professor of Ecclesiastical History, Dr Thomas Veech, at St Patrick's College, Manly.
Dr Veech led us through the long story of the Body of Christ surviving through it all, nor did he attempt to conceal the self-inflicted wounds, especially by the self-seeking members of the hierarchy in the Renaissance period. And thank God for the artists whose beautiful works, at least, survived – the Church almost did not. Hot on its heels came the Revolution, not a reformation at all: Trent did that.
God help us! Something had to be done, but if your mother is sick, you try to heal her - you don't walk out on her in her time of need.
What about today? It seems there was a pro-divorce lobby at the Synod of Bishops. Do these successors of the apostles not know that marriage is God's holy institution for man and woman, holily and permanently united by the Christ-given Sacrament, to help Him create citizens for Heaven.
Sexual activity for pleasure alone has created, and will go on creating, a multitude of frustrated, wounded people. And within marriage, this frustrates the purpose and beauty of what God designed to give life and deepen married love.
God forbid we should ever see Church leaders proposing as good, true or holy, anything that contradicts what Christ the King has firmly and clearly laid out for us as His way, truth and life.
Our so-called "simple faithful" are preserved from much of this appalling controversy, being busy doing good in and outside their families.
Our present times witness heroic youngsters setting out for missions in places like New Guinea, and in every parish, the good working fathers, the loving mothers, the patient old ones and the enduring sick, all so loving Jesus Christ and being embraced by Him.
Every parish is witness to these, to whom Paul referred when he told them, and still tells them all these ages later: "You are God's saints, he loves you ...".
No one can ever study adequately the history of the Catholic Church, for it is written not only in the lives and deeds of the powerful, saintly or self-seeking, nor even in the lives of the canonised few, and thank God for them, but in the day-to-day goodness of Christ's countless "little ones", who will stand at His right hand when the inevitable day dawns.
And what a selected prize He will present, especially to those who survived all those people who presented, in so many places, an anaemic Jesus Christ, to congregations and to classes of pupils.
It is on the shoulders of these "little ones" that Christ has laid His cross of truth today, and it is in their hearts that the good soil remains ready to give us our future "holy ones", and from them will come better marriages, priests and religious than we have seen for many a year.
It should be known that there are some of us who are eyewitnesses now to these wondrous happenings.
Let us trust the Church for the Holy Spirit will never leave her: "I am with you always, even to the end of the world."