The Protestant Reformers worked for many things, but perhaps the goal that they worked hardest to achieve was to restore the church’s confidence in Scripture. Stressing the unique inspiration and authority of the Bible, the Reformers sought to bring the Western church in submission to the Word of God after many years of the church’s following those who claimed too much authority for themselves. They recognized that Christians are perennially tempted to look for God’s power in things such as techniques, relics, the state, and individual personalities. But with respect to ministry, God has invested His power in one place, and that is His Word.
Isaiah 55:10–11 emphasizes the power that the Lord has invested in His revelation. The word that goes forth from the mouth of our Creator—which is Scripture, as Scripture is “God-breathed” (2 Tim. 3:16–17)—cannot fail to accomplish the Lord’s purposes for it. When God sends forth His Word in order to bring about a person’s salvation, that person will not finally resist His revelation. It will convert the man, woman, or child that God intends to save. At the same time, when the Lord sends forth His Word to someone He has not chosen for salvation, that revelation will result in the hardened person’s hardening his heart even further. God’s Word is powerful and effective both to reveal the way of salvation to Christ’s sheep and to hide it from the goats, those who have not been chosen from the foundation of the world for redemption (Matt. 11:25–27).
Just as the Word of God cannot fail to achieve the purposes for which it is given, Scripture cannot fail to teach the truth. The Scriptures are infallible, that is, incapable of teaching error. This is a necessary consequence of divine inspiration and the omnipotence of God. Scripture is God-breathed, and since God is truth Himself (Jesus, who is God incarnate, identifies Himself as truth; John 14:6), He is incapable of telling any lie. “Every word of God proves true,” as Proverbs 30:5 tells us.
The power of God guarantees the infallibility of His inscripturated Word. Some people argue that it is possible for Scripture to contain errors because it was written by human beings, and human beings are capable of erring. However, being capable of error and actually making an error are two different things. “All things are possible with God” (Mark 10:27), and surely God can inspire people to write in such a way that their words cannot teach error.