We receive the Old Testament (OT) as Scripture because Jesus authenticated it. How? For starters, He recognized the Jewish tripartite division of the Law, the Prophets, and the Psalms (Luke 24:44–45), and these contain all of the books of the OT. Moreover, Jesus quoted repeatedly from the OT, employing it to resist temptations, develop arguments, silence critics, teach lessons, reveal prophecies, defend truths, and expose needs. Finally, He accepted the OT as historical, referring to specific events (e.g., the first marriage, the flood, the destruction of Sodom, and the burning bush) and individuals (e.g., Adam, Eve, Abel, Abraham, Isaac, Jacob, Noah, Moses, David, Solomon, Elijah, Elisha, Naaman, and Jonah).
We receive the New Testament (NT) as Scripture because Jesus authorized it. How? He sent His disciples with the same authority with which the Father had sent Him (John 20:21). That is to say, He made His disciples His authorized representatives. As such, they served as the church’s foundation (Ephesians 2:19–22). And, in that role, they gave the NT to the church. B. B. Warfield explains, “We rest our acceptance of the NT Scriptures … not on the fact that they are the product of the revelation-age of the church, for so are many other books which we do not thus accept; but on the fact that God’s authoritative agents in founding the church gave them as authoritative to the church which they founded … . It is clear that prophetic and apostolic origin is the very essence of the authority of the Scriptures.”