Canonicity refers to the property by which a book belongs to the Holy Scriptures — recognized as divinely inspired, authoritative, and binding for faith and life. The canon of Scripture is not a human invention; God authored his Word through human instruments (2 Timothy 3:16), and the church's role was to receive and acknowledge what God had already produced. The tests historically applied — apostolic origin or connection, consistency with already-received Scripture, universal acceptance among the churches, divine self-authenticating authority — were not criteria that made a book canonical, but discernment tools to identify what God had already made canonical. The closed canon is a grace: God has spoken fully and finally in Scripture (Hebrews 1:1–2), and the warning against adding to or removing from God's Word stands at both the beginning and end of Scripture (Deuteronomy 4:2; Revelation 22:18–19).
CANON, n. A rule or law, in general. In ecclesiastical affairs, a rule of doctrine or discipline enacted by a council and confirmed by the sovereign. The canons of the Bible are those books which are acknowledged to be inspired by God and of divine authority. They form the rule of faith and practice. The word is from Greek kanōn, a rule or straight rod.
CANONICAL, a. Pertaining to a canon; according to the canon or rules; included in the canon of Scripture; constituting the genuine books of Scripture.
• 2 Timothy 3:16 — "All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness."
• 2 Peter 1:20–21 — "No prophecy of Scripture comes from someone's own interpretation. For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit."
• Deuteronomy 4:2 — "You shall not add to the word that I command you, nor take from it."
• Hebrews 1:1–2 — "Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son."
• Revelation 22:18–19 — "I warn everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues described in this book."
Contemporary culture treats the biblical canon as a political document — arguing that church councils arbitrarily "chose" which books to include, suppressing alternatives (the Gnostic gospels, the "lost books of the Bible") for power purposes. This narrative, popularized by works like The Da Vinci Code and academic skeptics, inverts the reality: the NT canon was substantially recognized by the second century, long before the councils that formally affirmed it, precisely because these books carried inherent apostolic authority. The councils didn't vote a book into authority — they recognized what had already been functioning as authoritative. The deeper modern corruption is the functional canon: Christians who have a de facto 67th book (cultural preference, pastoral personality, spiritual experience) placed above Scripture. When personal revelation, church tradition, or doctrinal novelty override the written Word, canonicity is abandoned in practice even if honored in theory.