If for so many centuries God revealed himself through the inspired writings that make up the Bible, is it possible that he may add more inspired writings today or in the future? It is a fair question and forces us to distinguish between what God can do and what God has said he will do.
God has the ability to reveal himself in whatever ways he wants. If he so desired, he could inspire more authors to write more Scriptures. But in the final book of the Bible, God makes it clear that it represents the end of this kind of revelation (see Revelation 22:18-19). The Bible, we say, is a “closed canon.” A canon is an authoritative collection of any author’s work; it is open as long as the author is adding to it, and closed when he has written his final word. In this case the author is God, and he has indeed written the last word he intends to write.
But that does not mean he has finished with all revelation of himself. To the contrary, the greatest of all revelations, the greatest of all revealings, is still to come. As Geoffrey B. Wilson says, “The only revelation from God which Christians still await is the revelation of Jesus Christ at his second coming.” That is a revelation we all still eagerly await! In fact, for centuries Christians have prayed, “Marantha! Come, Lord Jesus. Come and reveal yourself in that way!”