The question of how we know the 66 books in most Bibles are truly authorized as part of the canon, the authoritative collection of inspired Scripture, is fundamental. The canon was not unilaterally decided by the early Catholic Church; rather, the Church accepted a canon that was already set, as evidenced by the agreement among 25,000 ancient copies of the New Testament in various languages. Only a few books—James, Jude, II Peter, and II and III John—raised questions of canonicity due to authorship disputes, yet all are attested in early writings as authoritative. By AD 140, the visible church recognized all fourteen of Paul's letters and the four gospels, with the first historical list of all 27 New Testament books dating to AD 367, and official ratification by papal decree in AD 405. The Bible contains internal authorization protocols, including the prophecy in Isaiah 8:16, understood by the early church to mean the canon would be completed by the death of the original twelve apostles. The apostle John, the last to die around AD 100, is supposed to have gathered the 27 New Testament books and authorized their use in churches. Evidence suggests Peter began this canonization process as early as the mid-AD 60s, as II Peter 3:15-16 indicates Paul's epistles were already considered Scripture. This process potentially included nineteen books initially, with John later adding his writings, bringing the total to 24, leaving only Matthew's Gospel, James, and Jude, all written by apostles and without legitimate canonical issues. Protocols for canonicity include apostolic authorship, with exceptions for Luke and Mark, whose works were under the supervision of Paul and Peter, respectively. Another key protocol is internal unity, evident in the agreement of the New Testament books on doctrine, Christian living, history, and prophecy, forming a cohesive whole in 27 parts. Other suggested texts, like the Gospel of Thomas, disturb this unity and were excluded. General acceptance by the church also played a role, with the 27 books eventually authorized before the rise of the organized Catholic Church in the second century AD. The 39 books of the Old Testament underwent similar tests of canonicity, with a few like Esther and parts of Daniel questioned but ultimately recognized as reliable. Texts such as the Apocrypha and the Book of Enoch were deemed of lesser quality compared to the accepted books. The biblical books among the Dead Sea Scrolls further attest to the precision of their transmission through the ages, and scholarly debate on Old Testament canonicity has largely subsided to minor disputes.

The canonization of Scripture is a critical foundation for understanding the authority of the Bible, which consists of 66 books recognized as the inspired Word of God. The term "canon" derives from the Hebrew word qaneh and the Greek word kanon, meaning a reed or measuring tool, and by extension, a standard or benchmark of quality, excellence, and rightness. In the context of Scripture, it represents the authoritative standard used by the early church fathers to determine God-inspired texts and now refers to the accepted collection of those texts. Contrary to common belief, the Catholic Church did not authorize Scripture but merely accepted and codified what was already recognized as inspired. Ancient copies of the New Testament from various regions of the Roman Empire indicate that the canon was established prior to the Catholic Church's formal approval. Similarly, the true church of God did not authorize the canon but recognized and accepted the books that God Himself had inspired. Only God has the power to make something holy; humans can only acknowledge and respect it as such. Scripture itself provides evidence of its inspiration and authority. As Paul writes in II Timothy 3:16-17, all Scripture is given by inspiration of God and is profitable for doctrine, reproof, correction, and instruction in righteousness, equipping the man of God for every good work. Peter reinforces this in II Peter 1:19-21, stating that no prophecy of Scripture comes from private interpretation, but holy men of God spoke as moved by the Holy Spirit, ensuring its divine origin and unity. Historically, in the first few centuries after Christ, numerous manuscripts circulated within the Christian world, requiring both the Roman Catholic Church and the true church of God to discern authentic texts from spurious ones. The process of canonization for the New Testament involved rigorous tests of authorship, theological unity, spiritual reliability, and practical use over time. By AD 367, Bishop Athanasius listed the 27 books of the New Testament as we know them today, a decision later confirmed by the Synod of Hippo in AD 393. Remarkably, Syriac-speaking churches in the East, with little contact from Rome, arrived at the same 27 books through their own path. For the Old Testament, Jesus Christ Himself authorized the canon by referencing it as Scripture in Luke 24:44-45, dividing it into the Law of Moses, the Prophets, and the Psalms. His acceptance of the entire Old Testament, as evidenced by His quotations across the gospels, leaves no doubt in the true church of God about its scriptural status from the beginning. The New Testament canon adheres to specific internal protocols. First, broad-based acceptance by the church membership was evident early on, with Peter recognizing Paul's epistles as Scripture by AD 67 in II Peter 3:16. Second, the Protocol of First-Century Composition limits canonical writings to the lifetimes of the apostles, with John, the last apostle, sealing the canon around AD 100. Third, authorship under apostolic supervision ensures that even non-apostolic writings, like those of Luke and Mark, were overseen by apostles such as Paul and Peter. Finally, internal unity, or conformity to the rule of faith, demands that all accepted books agree on doctrine, Christian living, history, and prophecy, forming a cohesive whole without contradiction. Thus, there is no valid reason to doubt the authoritative nature of the 66 books of the Bible. As Peter and Paul affirm, these writings are God's prophetic word, inspired and trustworthy to guide us to the Kingdom of God.