The first letter of John is the second writing that we have of him in the Bible. His first writing is the Gospel according to John. After his first letter a second and third letter follow. Also the book of Revelation is from his hand. Therefore we have five writings in total from him in the Bible. His five writings are characterized by Who and what God is. In his Gospel he presents the Lord Jesus as God the Son. In his first letter he shows what eternal life is that God has given to the believer. That life is the Son Himself. That is the life you possess, for “he who has the Son has the life” (1Jn 5:11-12). In the book of Revelation we see God in His government.
Therefore, since we are now going to read and study his first letter, it is about the believer in whom the new life, i.e. the eternal life, is. The letter is not written to a local church, but to the individual believer, thus personally to you. At the same time you are addressed by him as someone who partakes of a company of believers, the family of God. The name ‘children of God’ also reflects that very well. Children who are born of the same parents are related to one another. Children of God are related to one another because they are born of God. That’s why they have life, eternal life, i.e. life in its most abundant form (Jn 10:10b). This eternal life is the Lord Jesus Himself (1Jn 5:20).
John shows in this letter how this eternal life works in you as a believer. To see how it expresses itself, you should look at the Lord Jesus. After all He is that new life in you. Therefore you also see that new life in the Gospels. Therein you see the Lord Jesus in His life on earth. Just as life is in Him and has been revealed by Him in the world, it also is in you. Therefore it cannot be otherwise than to manifest itself in your life in exactly the same way.
Now you may say that in your life – and that I say also about myself – the Lord Jesus is not always clearly visible. That is true when it comes down to the practice of your life of faith. However – and it is important to establish and hold that at the beginning of reading this letter – John does not speak in the first place about our practice, but about the essence or the nature of the eternal life you possess. That goes together with absolute statements.
I will clarify that to you with an example. If you want to examine what water is, what it is made of, you should not examine coffee. Coffee indeed consists nearly one hundred percent of water, but it contains elements that change the taste and color of water and thereby it is not one hundred percent water. You ought to take pure water to know what water consists of. In the same way, if you want to know what eternal life is, which is in you, you are not supposed to look at your practice. In your practice there are many elements that cloud the expression of that life. Therefore you should look at the Lord Jesus.
The Lord Jesus is that new, eternal life in its full form. In this letter John also speaks about the practice of your life of faith, but his starting point is the perfection of eternal life as it is in itself. This perfection is in the Lord Jesus and also in you, because you possess Him as your life. John writes penetratingly about this because in his day false teachers crept into the church with a false doctrine that affects the perfection of eternal life. They teach that Christendom is quite a nice start, but that they have more light and a higher knowledge about God.
John makes it clear that if you have eternal life, you have everything. The eternal life is complete and not ‘quite a nice start’ of your relationship with Divine Persons. John exposes the spirit of the antichrist. He gives you the proofs that you really do possess eternal life, that this life is from the Lord Jesus and that this life in itself is perfect and unchangeably the same. Therefore, do not let yourself be fooled by people who claim that they are able to help you to go deeper into the mysteries of the Godhead. There is no development of the truth of God about Christ into something that would be more perfect.