The New Apostolic Church affirms the Protestant biblical canon of 66 books: 39 Old Testament and 27 New Testament books. This canon includes the four Gospels, Acts, Paul's epistles, Hebrews, James, 1 and 2 Peter, 1, 2, and 3 John, Jude, and Revelation. The church does not recognize the deuterocanonical (Apocryphal) books as part of Scripture.

However, the NAC's understanding of authority is complex. While Scripture is affirmed as God's authoritative word, the church also teaches that Christ's authority is conveyed through the living Apostles. The teachings of the Chief Apostle and other ordained Apostles carry binding authority on doctrinal and practical matters. In this sense, the NAC's Catechism, which contains the teachings of the Apostles, supplements and interprets Scripture for the faithful.

This gives the NAC an unusual relationship to Scripture: it affirms biblical authority but not biblical sufficiency. Extra-biblical apostolic teaching is understood as necessary to guide the church correctly. This reflects the NAC's conviction that Christ's apostolic office continues in the present and that the living Apostles receive contemporary guidance from Christ for the church's needs.