Claiming that Scripture is true and complete should preclude evangelicals from turning to other sources for establishing thought and life. Yet many do just that. In cosmology, for example, a straightforward reading of Genesis 1-2 is often dismissed on the basis of modern evolutionary theories. In apologetics, philosophy and human reason frequently take precedence over Scripture. And in church growth, demographic surveys, marketing techniques, and a man-centered theology with a watered-down gospel override clear biblical truth.
To this list, the subject of morality and ethics must be added. Instead of looking to the Bible, many professing Christians look to psychology and sociology for supposed solutions to personal needs and social ills. The rise of postmodern thought has similarly skewed the church’s understanding of right and wrong - as an unbiblical tolerance (in the name of love) has weakened churches to the point where they are as soft on truth as they are on sin. Popular television shows, from Oprah to The Tonight Show to the average sitcom, have had a tangible effect (and not for the better) on how American Christians think through everyday issues. The political arena, too, has played a major role in shaping an evangelical understanding of morality, as words such as Republican and Democrat or liberal and conservative have come to redefine the difference between what is good and what is evil.
The fact is the far too many professing Christians live their lives, day in and day out, on the basis of something other than the Bible. As a result, their priorities reflect the world’s priorities, not God’s. Their patterns of behavior and their plans for future differ only slightly from those of their unsaved friends and neighbors. Their expenditures reveal that their perspective is temporal, and that they are vainly pursuing the elusive American Dream. Their shortcomings, when they admit them, receive the same fault-free labels that the world ascribes (“mistakes” or “diseases” or “addictions” rather than “sins”), as they search for answers in psychology, medication, or the self-help section of the bookstore. Though they adhere to an external form of traditional Christian moralism, there isn’t anything particularly biblical or Christ-centered about how they live.
Yet it is in the lives of sinners who have been transformed by the gospel of grace that a distinctly Christian ethic must be fleshed out. True Christianity is not defined on the basis of external moralism, religious traditionalism, or partisan politics, but on the basis of a personal love for Jesus Christ and a desire to follow Him no matter what the cost (John 14:15). It is only because believers have been transformed on the inside (through the regeneration of the Holy Spirit) that they are able to exhibit godliness in their behavior. And the world cannot help but take notice. As Jesus told His hearers in the Sermon on the Mount, “Let your light shine before men in such a way that they may see your good works, and glorify your Father who is in heaven.” (Matthew 5:16; df. 1 Peter 2:12).
The Heart of the Christian Ethic
The heart of the Christian ethic, of course, is the gospel. Only those who have been transformed from within (Titus 3:5-8), being indwelt by the Spirit of God (Romans 8:13-14), are able to exhibit genuine holiness (Galatians 5:22-23; 1 Peter 1:16). Biblical Christianity is not primarily concerned with external behavior modification (cf. Matthew 5-7), but with a change of heart that subsequently manifests itself in a changed life (1 Corinthians 6:9-11).
A true Christian ethic, then, is not possible without the regenerating work of the Holy Spirit. Unless the inner man is washed first, external morality and religious observances are only a superficial facade. Jesus rebuked the hypocrites of His day with these words: “Woe to you, scribes and Pharisees, hypocrites! For you are like whitewashed tombs which on the outside appear beautiful, but inside they are full of dead men’s bones and all uncleanness” (Matthew 23:27). Christ was not saying that behavior is unimportant. But rather that from God’s perspective, the heart is what matters most (cf.1 Samuel 16:7; Mark 12:30-31).
Of course, a heart that has been truly transformed by God will respond in love to His Son, Jesus Christ (cf. John 8:42). And those who love Jesus Christ will eagerly desire to follow and obey His commands (John 14:15), as found in His Word (cf. Colossians 3:16). A truly Christian ethic, then, eagerly affirms and applies the moral instructions found in the Bible. But it does not do so in an attempt to legalistically earn salvation (Isaiah 64:6). Rather, having received salvation as the free gift of God through faith in Christ (Ephesians 2:8-9), it readily obeys out of a heart of love (Ephesians 2:10).
If Christians are to live in keeping with who they are as children of God, they must live according to the Word of God through the power of His Spirit. No other source of wisdom or moral insight will do. By definition, they are people of the Book - and not just on Sundays, but every day of the week (cf. Isaiah 66:2).
Critics and skeptics (and sometimes even professing Christians) may claim that the Bible is not sophisticated enough for modern times. Such claims only expose their own foolishness. The Bible is absolutely pure, flawless, and error-free. There is no need to update, edit, or refine it. It is perfect. When I was in college I learned about philosophy. Almost every philosophy I studied was already long dead. I also had to learn about psychology. Almost every form of psychotherapy I read about back then is now obsolete and has been replaced by new theories or techniques. But there’s one thing that never changes, and that is the eternal Word of God. It is always relevant.
John MacArthur, Right Thinking In A World Gone Wrong, pp. 7-9, 12.