There are many sources of debate on this matter, and I am currently investigating these points of contention. In so doing, I was listening to some lectures on sola scriptura by Scott Hahn, and was pointed to a very interesting passage in the Gospel of John, in chapter 11.
47So the chief priests and the Pharisees gathered the Council and said, "What are we to do? For this man performs many signs. 48If we let him go on like this, everyone will believe in him, and the Romans will come and take away both our place and our nation." 49But one of them, Caiaphas, who was high priest that year, said to them, "You know nothing at all. 50Nor do you understand that it is better for you that one man should die for the people, not that the whole nation should perish." 51He did not say this of his own accord, but being high priest that year he prophesied that Jesus would die for the nation, 52and not for the nation only, but also to gather into one the children of God who are scattered abroad. 53So from that day on they made plans to put him to death.
Here we see that John takes a huge point for granted. He argues that as high priest, Caiaphas spoke prophecy by the nature of his office. Despite the fact that he plotted "eliminating" the problem of Jesus, he was still able to speak prophecy. In a sort of double entendre, Caiaphas' words meant that he was both approving the conspiracy to frame Jesus for a crime and speaking of Christ's sacrifice for our sins.
I do not have the time nor the space to argue whether this gift applies to the Papacy or other extrapolations from this basic point. The main thing that I would ask you to think about is this basic idea of how God has spoken to His people. Many have said that the Old Testament period was one plagued by the faithful fighting the establishment, and that where we stand today is no different. This passage shows that despite personal failings, the high priest of Israel was given a gift to speak prophecy.
It is similar to what Christ said to His disciples in Matthew 23:
1Then Jesus said to the crowds and to his disciples, 2 "The scribes and the Pharisees sit on Moses’ seat, 3so practice and observe whatever they tell you— but not what they do.
The leaders of God's people historically provided a basis for sorting out disagreements by speaking reliable words to the point that even while they opposed Christ, Christ was able to commend their words (but NOT their actions) to His disciples.
And so we see that the idea that history is full of silent periods where we are left with sayings from the past is even further silenced.
Thank you, Jesus, for bringing Your truth to all ages. Open our eyes to see all of Your truth.