Several months ago, my oldest son ordered a wallet online. What was surprising to both of us was that the wallet arrived with a $100 bill in the billfold. However, we quickly determined that the $100 bill was a counterfeit. How did we come to that conclusion? Well, we knew what a real $100 bill looked and felt like. While this counterfeit currency had the appearance of being genuine, it was easy to determine it was counterfeit because we knew the true characteristics of a real $100 bill. Through testing the size, appearance, and feel of the bill, we could determine that it was a counterfeit.

What does this have to do with Christianity? There are many counterfeit versions of Christianity, so we need to know how to determine the true from the false. The best way to do that is to know the tests of true Christianity. Let’s look at how the apostle John unpacks this in his first epistle with these notes from the Welwyn Commentary.

Tests of True Christianity

It is probably fair to say that many people hear a teacher and say to themselves, ‘This person is a nice person. I will believe what he says.’ That is a most dangerous method. In this section of Scripture (1 John 2:18–27), John sets out for us three methods of discerning truth about Christ.

Test 1 – Profession Concerning Jesus Christ

The first test is the profession concerning Jesus Christ: ‘Who is a [literally, “the”] liar but he who denies that Jesus is the Christ? He is antichrist who denies the Father and the Son. Whoever denies the Son does not have the Father either; he who acknowledges the Son has the Father also’ (2:22–23). The false teachers whom John had in mind were certain Gnostics who believed that the divine Christ had descended on the man Jesus at his baptism, then left him before the crucifixion. Hence there was no real incarnation—Jesus Christ is not trusted as one person in two natures, human and divine.

John is teaching that the God-man Jesus Christ is the one and only way to the Father; he alone reveals the Father to us (Matthew 11:27; John 1:18; 14:9). This condemns Freemasonry, which teaches its adherents to call upon God without mentioning the name of Christ. It condemns prayers at inter-faith services where the name of Christ is omitted for fear that it might cause offence. It condemns the New Age movement, which uses Christian terms and even speaks of Christ, but teaches that the person is to let go of himself and allows his higher self to take control. Similarly, when New Agers speak of Christ, they mean the divine Christ that they claim descended on Buddha, Mohammed, Jesus and many others.

It is not enough for people to acknowledge certain Christian expressions while discarding the Bible’s clear teaching that the man Jesus is the divine Christ, and is the only mediator between God and sinful human beings. An antichrist rejects the Son and so rejects the Father also.

Test 2 – Testimony of the Spirit

The second test concerns the testimony of the Holy Spirit. John is writing to Christians, and Christians have the Spirit of God indwelling them: ‘But you have an anointing from the Holy One, and you know all things. I have not written to you because you do not know the truth, but because you know it, and that no lie is of the truth’ (2:20–21). This is the Spirit whom Jesus promised: ‘And I will pray the Father, and he will give you another Helper, that he may abide with you for ever—the Spirit of truth, whom the world cannot receive, because it neither sees him nor knows him; but you know him, for he dwells with you and will be in you’ (John 14:16–17). As Jesus was anointed with the Spirit, so too Christians are anointed with him.

Because of the Spirit’s indwelling them, Christians ‘know all things’ (2:20, NKJV). The NKJV’s rendering of verse 20 fits in with the meaning of verse 27: ‘But the anointing which you have received from him abides in you, and you do not need that anyone teach you; but as the same anointing teaches you concerning all things, and is true, and is not a lie, and just as it has taught you, you will abide in him.’ John is not abolishing human teachers; the New Testament church has a decided place for them (see Ephesians 4:11; 1 Timothy 3:2). After all, even John himself wrote this epistle to teach his readers! What he is saying is that the real teacher is the Holy Spirit. The Holy Spirit indwells the Christian as a kind of divine lie detector.

With or Without the Spirit

Without the Spirit, people will believe in a Christ of their own imagination, one who fits in with their own whims. With the Spirit, the Christian will discern all things—not exhaustively, of course, but comprehensively. The Christian may be duped for a time, but he will hear alarm bells when someone says, ‘What matters is that we all believe in God and that we have a unity of the Spirit—those are the main things.’ The Christian senses that such sentiments are inadequate and ambiguous and will finally reject them. Without the Spirit, we shall be blown about by every wind of doctrine and the latest fad on the church scene. That is why it is impossible to get through to a person without the Spirit of God. Such a person does not understand, and cannot understand, the things of God (1 Corinthians 2:14).

Test 3 – Holding onto Apostolic Teaching

The third test is found in verse 24: ‘Therefore let that abide in you which you heard from the beginning. If what you heard from the beginning abides in you, you also will abide in the Son and in the Father.’ Christians aim to believe and teach what the apostles believed and taught. There is no warrant for novelties, fashions and additions which tickle itching ears. Christianity cannot be updated to make it relevant; all that needs to be done is that it be applied faithfully.

Back in the nineteenth century Charles Hodge boasted of Princeton Seminary: ‘I am not afraid to say that a new idea never originated in this seminary.’ That might have been expressed less baldly, but it does emphasize the need to remain faithful to the apostolic word. Neglect this word, and you are a sitting duck for any sort of teaching—religious or irreligious. That is why we must test all teaching by the light of God’s inerrant and sufficient Word (Acts 17:11).

Beware of the Deceivers

John wrote as he did because there are people who are deceiving themselves and who wish to deceive others: ‘These things I have written to you concerning those who try to deceive you’ (2:26). There are teachers who profess to be Christians but who are not. They may have their own television ‘ministries’, but all is not as it appears on the surface. Our Lord himself warned us: ‘For false christs and false prophets will rise and show signs and wonders to deceive, if possible, even the elect’ (Mark 13:22).

We need to beware, for these men and women will not have ‘false teacher’ neatly inscribed on their foreheads. That is why Christ tells us to take heed, for we need to be told about these things beforehand (Mark 13:23). The Christian life is not all straightforward; it is not all plain sailing. We need to test all things that we hear from teachers (1 Thessalonians 5:21). We can do this by testing their profession of Jesus as the Messiah and God’s only begotten Son, by the inward testimony of the Holy Spirit in us and by the faithfulness of these teachers to the apostolic word of Scripture.

This is not to be nit-picking and uncooperative; this is to exercise Christian discernment. Those who swallow everything will take in spiritual poison. Deceivers will not necessarily attack the faith openly, but they are still antichrists. Beware of them; know that the truth is of Jesus Christ, witnessed to by his Word and his Spirit. It is a fallen and dangerous world that we live in, and we need to be armed.

Get More Truth with the Welwyn Commentary

The Welwyn Commentary is an expository commentary from Evangelical Press. This is a great resource for understanding and applying God’s Word. You can purchase this series on our website through the link below.