Most people are familiar with the warning in the Book of Revelation:
"And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book." Revelation 22:19
Many people assume this scripture refers to the Bible canon as a whole, and therefore claim that the Bible is the fullness of God's Word and that direct revelation from God is closed. The Catholics also believe that there is no more direct revelation, they believe that the Bible is the fulness of God's written Word, but they rely on Tradition, which is passed down through apostolic succession, for the interpretation of scripture, and believe scripture and Tradition combined provide them with a fullness of truth. Then there are other denominations that claim the heavens are not closed and that God continues to provide new revelations to prophets on earth, and that the Bible is not the complete word of God, and therefore rely on other books in addition to the Bible as well as new revelations—as they are revealed—for a fullness of truth.
What are the biblical arguments that the Bible canon is not closed?
Note: When I say "Bible canon" I mean to communicate canonical books or scriptural canon, not changing the books within the Bible, but receiving new books and revelations as scripture that compliment the Bible.