Scripture is the Word of God
The tablets were the work of God;
the writing was the writing of God,
engraved on the tablets. EXODUS 32:16
Christianity is the true worship and service of the true God, humankind's Creator and Redeemer. It is a religion that rests on revelation: nobody would know the truth about God, or be able to relate to him in a personal way, had not God first acted to make himself known. But God has so acted, and the sixty-six books of the Bible, thirty-nine written before Christ came and twenty-seven after, are together the record, interpretation, expression, and embodiment of his self-disclosure. God and godliness are the Bible's uniting themes.
From one standpoint, the Scriptures (Scriptures means "writings") are the faithful testimony of the godly to the God whom they loved and served; from another standpoint, through a unique exercise of divine overruling in their composition, they are God's own testimony and teaching in human form. The church calls these writings the Word of God because their authorship and contents are both divine.
Decisive assurance that Scripture is from God and consists entirely of his wisdom and truth comes from Jesus Christ and his apostles, who taught in his name. Jesus, God incarnate, viewed his Bible (our Old Testament) as his heavenly Father's written instruction, which he no less than others must obey (Matt. 4:4, 7,10; 5:19-20; 19:4-6; 26:31, 52-54; Luke 4:16-21; 16:17; 18:31-33; 22:37; 24:25-27, 45-47; John 10:35), and which he had come to fulfill (Matt. 5:17-18; 26:24; John 5:46). Paul described the Old Testament as entirely "God-breathed"--that is, a product of God's Spirit ("breath") just as the cosmos is (Ps. 33:6; Gen. 1:2)--and written to teach Christianity (2 Tim. 3:15-17; Rom. 15:4; 1 Cor. 10:11). Peter affirms the divine origin of biblical teaching in 2 Peter 1:21 and 1 Peter 1:10-12, and so also by his manner of quoting does the writer to the Hebrews (Heb. 1:5-13; 3:7; 4:3; 10:5-7, 15-17; cf. Acts 4:25; 28:25-27).
Since the apostles' teaching about Christ is itself revealed truth in God-taught words (1 Cor. 2:12-13), the church rightly regards authentic apostolic writings as completing the Scriptures. Already Peter refers to Paul's letters as Scripture (2 Pet. 3:15-16), and Paul is apparently calling Luke's gospel Scripture in 1 Timothy 5:18, where he quotes the words of Luke 10:7.
The idea of written directives from God himself as a basis for godly living goes back to God's act of inscribing the Decalogue on stone tablets and then prompting Moses to write his laws and the history of his dealings with his people (Exod. 32:15-16; 34:1, 27-28; Num. 33:2; Deut. 31:9). Digesting and living by this material was always central to true devotion in Israel for both leaders and ordinary people (Josh. 1:7-8; 2 Kings 17:13; 22:8-13; 1 Chron. 22:12-13; Neh. 8; Ps. 119). The principle that all must be governed by the Scriptures, that is, by the Old and New Testaments taken together, is equally basic to Christianity.
What Scripture says, God says; for, in a manner comparable only to the deeper mystery of the Incarnation, the Bible is both fully human and fully divine. So all its manifold contents--histories, prophecies, poems, songs, wisdom writings, sermons, statistics, letters, and whatever else--should be received as from God, and all that Bible writers teach should be revered as God's authoritative instruction. Christians should be grateful to God for the gift of his written Word, and conscientious in basing their faith and life entirely and exclusively upon it. Otherwise, we cannot ever honor or please him as he calls us to do.
Concise Theology. J.I. Packer.Tyndale House Pub., Inc. Wheaton, IL. 1993. Revelation. Pages 3-5.