The Canon of the Old Testament
While the New Testament does not provide a list of canonical books, it does make clear that Our Lord authorized the Apostles to make authoritative judgments about religious law. The most pointed example is to be found in Matthew 16:
"And I tell you, you are Peter, and on this rock I will build my church, and the powers of death shall not prevail against it. I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven."
Leaving aside for the moment the significance of the "keys of the kingdom of heaven," let us focus on the concept of "binding" and "loosing." In first-century Palestinian Judaism, the terms "bind" and "loose" referred to authoritative decisions about religious law. Religious law was (and is) called halakhah, from the verb halakh, "to walk." Halakhah is then, the way one "walks," that is, how one behaves. To "bind" meant to prohibit a behavior, to "loose" meant to permit it. In practice, the Pharisaic scribes generally bound and loosed for the common people of Israel: Jesus refers to their exercise of religious authority (and even partially endorses it!) in Matthew 23:
"The scribes and the Pharisees sit on Moses' seat; so practice and observe whatever they tell you, but not what they do; for they preach, but do not practice. They bind heavy burdens, hard to bear, and lay them on men's shoulders; but they themselves will not move them with their finger."
The point of Matthew 16:18-19 is, then, that Jesus is investing Peter—and later, the apostles with him (Matt 18:18)—with the authority to make binding decisions concerning religious law for the people of God. One such question of religious law was the correct list of inspired books, i.e. the canon.