Praised be Jesus in Mary, now and forever.
Today we celebrate the Feast of one of the Twelve Apostles, St. Bartholomew, who is identified with the Nathanael about whom we read in the Gospel today. He was from Cana in Galilee, and he died probably in Armenia, as the Tradition tells us, but the facts of the lives of the Apostles are very uncertain. In any case, it is very probable and likely that he died in Armenia, where he had converted the king to Christianity. And those who didn't like that political change, because converting to Christianity meant also a political change in the kingdom, enacting just laws and a just society, those who didn't like that change had him killed and skinned alive specifically. So a very cruel martyrdom that he suffered.
Being one of the Apostles, Bartholomew, he was a witness of Christ's life from his baptism all the way until his ascension. And it's crucial that the Apostles be witnesses of the life of Jesus, because Jesus taught by his entire life, by the words that he spoke, but also by the actions he performed, by the examples that he gave to the Apostles. And it's important for the Apostles to be witnesses of the life of Jesus, because later on, they had to teach about Jesus by their words and their examples. They had to speak what they heard Jesus speak and do what they saw Jesus do. And God, in fact, reveals himself to us not just through the Bible, and this is in no way diminishing the importance of the Bible.
The Bible is the word of God, but God has spoken to us more than is contained in the Bible, and we call this in theology the material insufficiency of Scripture. You may be surprised to hear this term, but it's actually Catholic doctrine. The Bible alone is insufficient.
Not as far as meaning, because without something else, we don't know what the Bible means.
There are so many passages that are undecipherable unless we have handed down from the authors the meaning, which we can call tradition. The authors of the Bible handed down not just the book, but the meaning. The authors gave to their audience the written book and answered the questions about the books as well, and that meaning has been handed on in the Church, in tradition, and in the magisterium. The Bible alone is, again, insufficient, and meaning has to also be transmitted along with it. But also, as far as content, the Bible is insufficient.
God has revealed to us more than is contained in the Bible. I'll give two examples of that in just a second, but to use an expression that encapsulates this very well, it's one of these expressions that's easy to remember. It's like a play on words, a phonetic play on words, that when God became man, he didn't just wish to leave us a manual. He wanted to be our Emmanuel. He wanted to be God with us, not just leave us a textbook and then disappear. God wanted to be our Emmanuel, God with us. Words, examples, and then, as we shall see, he wanted to extend that presence until the end of time.
The Second Vatican Council says that the apostles taught the way our Lord taught, by their oral preaching. So the apostles preached, but also by their example. For example, they read certain books of the Bible as inspired. Others, they rejected. This is the question of the canon of Scripture. The Bible doesn't tell us what the Bible is. The Bible doesn't give us an inspired table of contents. The Bible itself is insufficient to tell us which books are inspired by God. That comes from Tradition with a big T. And again, the apostles read certain books, didn't read others. 
Moreover, the observances of the apostles tell us that Sunday is the day of worship for Christians, because the Bible doesn't tell us that. In fact, the Bible says the Sabbath day is. And yet, Christians worship on a Sunday. Why is that? Because the Bible itself is insufficient. The apostles received from our Lord the revelation that Sunday was the Lord's day, because the resurrection was like a new creation. The apostles observed that, taught the community to observe that. Their example became a means of transmitting the revelation they themselves had received from Christ. And this is again tradition, and then later on the magisterium and the successors of the apostles. So just as when he was on earth, there was no way to find Christ, except to find him surrounded by his apostles. Christ on earth was always surrounded by his community, the apostles, his early Church. So today and always, Christ is always surrounded by his Church. Christ is always in the midst of his community. Here, almost as a humorous aside, but that's serious, it would deserve another sermon, but that community, of course, is the Church. But just as back then, the apostles misbehaved, so the successors of the apostles, of course, they misbehaved.
Despite that fact, even though the successors of the apostles misbehaved as much as the original apostles did, still this is Christ's community. And just as the apostles didn't have a right to command anything against the will of Christ or to teach anything against the teaching of Christ, in fact, they were reproached by our Lord for that. When they tried to prevent the children from coming to Christ against Christ's will, Christ reproached them and said, no, let the children come to me. And when St. Peter, right after he was made Peter, says, Lord, it's not a good idea for you to go to Jerusalem to suffer and to die. Our Lord said to him, get behind me, Satan. So just as the original apostles had no right to command against the will of Christ or to teach against the will of Christ, neither do their successors. But again, that's a different sermon. The point is that Christ is present in the world today, not alone, but like he was 2,000 years ago, in the midst of a community, in the midst of the apostles, in the midst of the Church.
That's why we call the Church the sacrament of salvation. It extends Christ's presence in the midst of that community down to our time and until the end of time. The Church is a visible representation of that community that we have to love, the Church community. We have to love our Catholic Church. This is the community of Christ, established by Christ, set up by Christ, loved by Christ, with which Christ united himself inseparably. We have to enter in this community, remain in this community, live and die in this community, this family of Christ. For that, we prayed at the beginning of Mass, and with that prayer, we close this little reflection. This is the Collect of the Mass.
Strengthen in us, O Lord, the faith by which the blessed Apostle Bartholomew clung wholeheartedly to your Son, and grant that through the help of his prayers, your Church may become for all nations the sacrament of salvation. Through Christ our Lord. Amen. 
Praised be Jesus in Mary, now and forever.