All Scripture is God-breathed: This means it comes directly by God's own speech (see also Hebrews 4:12–13; 2 Peter 1:20–21). This does not remove the role of human authors. It confirms that God is fully responsible for his word, and that scripture is true, reliable, and has authority. It is permanent and powerful because it comes from God. Its message is plain and consistent about Jesus Christ (see Luke 24:25–27, 44; John 5:39–40; Acts 3:24; 1 Corinthians 15:3–4).
It has the power to bring salvation and inspire true faith. People must not abuse it, as some false teachers have done (2 Timothy 4:2–4; 1 Timothy 1:4–7; compare 2 Peter 3:16). But God's leaders must teach it correctly (2 Timothy 2:2, 15).
As a result of its inspiration from God, all Scripture is useful. Both the Old Testament and the New Testament together guide and teach Christians in this life.