In the long warm talk Jesus had with the Apostles after the Last Supper he said, “The Holy Spirit whom the Father will send in my name will teach you everything and remind you of all that I told you.” A little further on he came back to that subject saying, “I have much more to tell you, but you cannot bear it now; but when he comes, the Spirit of Truth, he will guide you to all truth.”
A dozen years later the Apostles remembered those words when they came up against a problem for which Jesus had not prepared them. The problem was that they and Jesus had always been Jews eating only kosher food, but suddenly they were confronted with pagans who wanted to become Christians without becoming Jews. They recognized this as one of those situations for which Jesus had not given them any direction because he knew that back then they would not have been able to understand.
So they started telling each other that the Holy Spirit would show them the right way to deal with non-Jewish Christians, and to avail themselves of his direction, they saw they had better come together. We read about that in Chapter Fifteen of the Acts of the Apostles. In our Bible the heading for that chapter is Council of Jerusalem.
At the end of the Council of Jerusalem they said that Gentile converts were free to eat foods Jews couldn’t eat. They wrote, “It is the decision of the holy Spirit and us not to place on you any burden.”
In twenty general councils over two thousand years the Church has depended on the Holy Spirit to lead them to the right way for dealing with unexpected difficulties. At the Second Vatican Council forty years ago bishops pleaded with the Holy Spirit to show them how they had to behave in a modern world.