The apostle John wrote his first letter to a group of Christians struggling with idolatry. As he closed his exhortation, he issued a stern warning: “Little children, keep yourselves from idols” (1 John 5:21).

To those who are not versed in a biblical understanding of idolatry, that may sound strange, and it may appear at odds with the rest of 1 John’s contents. John defined his readers as “little children,” which implies that he considered them to be Christian. Was there really a danger of Christians in the first century bowing to graven images? And why would he suddenly raise this issue, having said nothing about it before that point? A biblical understanding of idolatry will go a long way toward resolving these tensions.

It is easy for us to see how non-Christians can be implicated in idolatry. The God of the Bible is explicit: “You shall have no other gods before me” (Exodus 20:3). To worship anyone or anything but the God of the Bible is idolatry. The Muslim who worships Allah or the Hindu who bows down to thousands of manifestations of god are clearly guilty of idolatry. The atheist who refuses to acknowledge and worship Yahweh is guilty of idolatry. This is easy for us to understand. But “little children”? How can Christians be guilty of idolatry.

Clearly, idolatry must be a temptation for Christians, or John would not have warned his “little children” against it. But when do Christians fall into this trap? The Heidelberg Catechism says that “idolatry is having or inventing something in which one trusts in place of or alongside of the only true God, who has revealed himself in the word.” This definition of idolatry reveals at least two ways in which Christians can be tempted to idolatry.

First, we are sometimes guilty of placing other things—even good things—alongside God. Jesus illustrated this truth when he said,

Whoever loves father or mother more than me is not worthy of me, and whoever loves son or daughter more than me is not worthy of me. And whoever does not take his cross and follow me is not worthy of me.  Whoever finds his life will lose it, and whoever loses his life for my sake will find it.

(Matthew 10:37–39)

Paul spoke of some whose “god is their belly” (Philippians 3:9). Their appetite so consumed them that the apostle identified them as worshipping their stomach. We are sometimes tempted to afford to things equal or more value than God: money, sex, power, education, security, etc. When anything is as important to us as God is, we are guilty of idolatry.

Second, we are sometimes guilty of claiming to worship the true God when we in fact do not worship him as he has revealed himself in Scripture. When we project our ideas of who God ought to be onto God, we are guilty of idolatry. This was John’s particular burden in 1 John.

Our idolatry is often rooted in our illusion of control. We believe that control can be achieved with rituals, prayer, or adherence to ethical standards. We think that our devotion and obedience will secure divine favour. In an unpredictable world, religion seems to afford us a measure of control.

Against this illusion stands the scriptural revelation of an uncontainable, uncontrollable, omnipotent God. The God of the Bible defies our logic and will not bow to our illusions of control. There is no set formula in biblical Christianity that guarantees favourable providence. The gods of the pagan nations in Scripture promised predictable outcomes based on set behaviours and rituals, but the God of the Bible makes no such promises.

It is precisely for this reason that we are forbidden from fashioning images of the living God (Exodus 20:4–6). When we create an image of God, we project our understanding of God onto that image. As the French philosopher Voltaire said, “If God has made us in his image, we have returned the favour.” We unwittingly refashion God in our image because a god who is just like us—who looks, thinks, acts, believes, and judges like we do—is no threat to us. An idol demands no change, and we are happy to worship a god who will leave us alone.

The God of the Bible is different. He expects us to worship him as he has revealed himself, not how we imagine him to be. John wrote as an eyewitness to the ministry of Christ. He wrote as one who had heard Christ, seen Christ, and touched Christ. As an apostle, he was in a position to tell us who Christ actually was.

In the first two centuries, the biggest threat to biblical Christianity was Gnosticism. Not all branches of Gnosticism were a direct threat to Christianity, but certain streams claimed to be higher forms of Christian truth. Their doctrines, however, flatly contradicted apostolic claims.

Gnostics agreed that Jesus was not God become flesh, because in Gnostic thought the flesh was inherently evil, while the spirit was inherently good. Some Gnostics taught that the Christ only appeared to have a human body. Some taught that Jesus was merely a man whom the Christ spirit filled at his baptism. Some taught that the Christ spirit left him at the cross, while others taught that it wasn’t actually Jesus, but someone else, who was crucified. Some Gnostics ignored the resurrection; others spiritualised it.

Regardless of the particular form, Gnosticism was a radical departure from what the apostles taught. John’s readers were tempted to believe Gnostic lies, but John wrote to exhort them to believe apostolic truth. The apostles had seen Christ; the Gnostics had not. They had heard Christ teach; the Gnostics had not. They had touched Christ; the Gnostics had not. If there was to be competition between the apostles and the Gnostics as to true teaching about Christ, it was obvious that the apostles should be believed.

John offered clear insight into the person and work of Christ. The eternal destiny of his readers rested on what they believed about Christ. If they believed in the Christ of the apostles, they would inherit eternal life; if they embraced the Christ of Gnosticism, God’s wrath remained on them. It is against this backdrop that John issued his final appeal: “Little children, keep yourselves from idols.”

In the context of 1 John, then, an idol is not a graven image of a calf or an ox but a superficial view of Jesus Christ. John had told his readers who Jesus Christ is; if they embraced Gnostic—or any other—views of Jesus they were guilty of idolatry.

With this understanding, we do well to ask ourselves if our understanding of Jesus is firmly rooted in apostolic teaching. If we want a Christ who is love but shows no wrath, we are guilty of idolatry. If we want a Christ who forgives and receives all regardless of faith and obedience, we are guilty of idolatry. Our ideas of God and of Jesus Christ must be firmly rooted in Scripture, or else we are guilty of worshipping a god of our own making. “Little children, keep yourselves from idols.”