It seems, said my friend, that the Church contradicts itself. On the one hand, Catholic teaching declares revelation complete with the close of the apostolic era. Yet consider the canonization of, say, Joan of Arc. It appears a Catholic must believe one of the following:
1. Revelation continues. It was revealed to the Pope in 1920 that Joan of Arc was in heaven.
2. Revelation ended with the apostles, but before the Ascension, Christ gave Peter a long list of those who would eventually be canonized and Joan's name was on the list.
3. There is no revelation concerning Joan of Arc and we have no way of knowing where she is now.
To get to the bottom of this apparently insoluble mystery we have to understand what the Church means by "new revelation" and what it is up to in canonizing saints. When the Church declares that revelation is closed and that no further word from God is forthcoming, many people think it is saying that God clammed up in 90 AD, retired in stony silence to the utmost heaven of heavens and ceased showing himself to us mortals.
In reality, though, the Church means that, in offering His Son Jesus and in setting forth the fullness of the gospel through Him and His Apostles, God has already given us possession of the fullness of His gift to us, the gift of Himself (and once God has given God Himself, there's not much to add.)
If this is unclear, perhaps an illustration will help us get the hang of it. Compare, for example, the Catholic gospel with the Mormon picture of things. For the Catholic, the gospel in New Testament times was like a newborn baby. The Church has never denied the reality that baby must grow up and experience life more deeply. Indeed, the Lord Jesus assured us that He would lead the Church into all truth (John 16:13) and that the Church would deepen and grow in faith and understanding. But He said that this would happen, not via "new revelation" but via the Spirit reminding us of everything He has already said to us (John 14:26).
In contrast, Mormonism really does assert that God is still showing radically new things which have never ever been revealed before. Mormon belief in new revelation quite openly adds really new (and frequently contradictory) things to the deposit of faith handed on by the apostles. It adds, for example, new scriptures, a new announcement that God the Father was once a man like us and a declaration that the three persons of the Trinity are, in fact, three separate Gods. In short, Mormonism proclaims an evolving, polytheistic Godhead in flat contradiction to the revelation of the Old and New Testaments.
Now this is a different kettle of fish than the Catholic view of development of doctrine. For Mormonism quite happily seeks to innovate where the Church (beginning with the Apostles) has always sought to conserve and cultivate. What's the difference? The difference is between nurturing a baby to maturity and performing radical surgery on the baby to add an extra leg or two more pairs of eyes. Just as it is natural for a baby boy to eventually grow a beard, so it was natural for the Church to eventually grow, say, the doctrine of the Trinity from the seed of the apostolic preaching. For both the beard and the doctrine were in baby's genes from the start. But it does not therefore follow that it is natural for baby to grow a tumor. Nor is it natural for the Faith to suddenly proclaim a "new revelation" in flat denial of the preaching of Moses, the Prophets, Jesus and the Apostles. For Catholics, the baby Faith needed the food and drink of the sacraments and the exercise of holiness to mature into the whole measure of the fullness of Christ. For those who believe in new revelation, the baby needed an ever-increasing number of noses, fingers, ears, and eyes.
Very well then, the Church does indeed proclaim the completion of public revelation with the end of the apostolic age. But to assert that there is no new public revelation does not mean that the Holy Spirit has been silent since the end of the apostolic era. Rather, it means that He is not saying anything different, any more than He is adding a fifth season to the original four. In short, as He creates spring anew every year (though it is millions of years old) so, in the gospel He is continually saying the same new thing again and again until we really hear it. And with each generation, men, women and children have really heard it and been made new--which takes us back to the canonization of St. Joan and the other saints.
What exactly is canonization? Canonization is not new revelation, but an exercise of the Church's gift of discernment. In other words, it has been given to the Church to "discern spirits" as Paul says (1 Cor 12:10) and to "know them by their fruits" (as Jesus specifically commands [Matt 7:15-20]). In canonization, the Church formally declares "Here was someone who obeyed the apostolic gospel we have always preached." This is not to alter the content of that gospel either by addition or subtraction. It is simply to do what God both commands and empowers the Church to do when St. Paul prayed for the Church that "the eyes of your heart should be enlightened in order that you may know the hope to which He has called you, the riches of His glorious inheritance in the saints" (Eph 1:18). Obviously then, it follows that God will hold before our eyes, some of the more sterling examples of those saints who displayed faithfulness to the gospel.
How then does the Church know St. Joan is in heaven? Not by "new revelation," but by old revelation. For Christ promised heaven long ago to anyone who obeyed His gospel. If the Church, which is the keeper of that gospel, discerns obedience to it by Joan's fruits, then the Church (according to the Lord's own word) is gifted and empowered to recognize such a fact publicly for God's glory and our spiritual enrichment.
But in saying this, we must add a qualification. For at this point some people are suddenly inclined to read an equal and opposite significance into the Church's silence concerning everyone else, as if only St. Joan and the small number of formally canonized people are in heaven. But this is not so. Indeed, the Church prays and hopes for the salvation of all (though it cannot promise this since salvation depends on our free acceptance or rejection of grace). So the Church's silence is just that: silence. It implies nothing whatsoever about the destiny of the rest of humanity.
To illustrate once more, we may say that, in surveying the galaxy of humanity, the Church is like an astronomer observing a supernova. It can exclaim of some saint "That's a supernova!" But in so doing it is not thereby denouncing all the other more obscure stars and planets which may be, in God's sight, just as splendid. This is what accounts for the fact that the Church has always encouraged prayers to devoted, yet non-canonized elders in the Faith such as beloved grandparents who died in Christ Jesus. My wife's Grandpa Antonine is, for us, a saint though he will probably never be canonized.
It is this generous and circumspect open-endedness concerning the mercy of God which also accounts for the interesting fact that the Church, while recognizing numerous saints, has never made a similar pronouncement concerning who is and is not damned. There are no formally defined "anti-saints." Not even Hitler or Judas Iscariot (who we would think were shoo-ins for the post). Does this have some deep significance in guessing the eternal reward of these two gentlemen? Is the Church hinting at a covert belief in universalism? No. It is simply placing them in the hands of God who knows what to do with them (and praying He have mercy on their souls).
We do well to imitate this. For we are given the task, not of judging, but of emulating the wisdom of the Church and acknowledging that we simply do not know and are not competent to consign anyone to Hell, even Hitler. Rather, it is for us to pray for such men and then, turning our focus away from their monstrous crimes, obey the word of the Lord and look steadily, not at earthly or hellish things, but at the treasury of the saints to which our Church so enthusiastically points. For in them we see that which God desires to give us: His unchanging gospel and its incomparably great power for us who believe (Eph 1:19).