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 there still follow a second and third letter. 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’s 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 present. The letter is not written to a local church, but to the individual believer, thus personally to you. At the same time you are being addressed by him as somebody who partakes of a company of believers, namely 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 and indeed eternal life, i.e. life in its most abundant form (Jn 10:10b). That eternal life is the Lord Jesus Himself (1Jn 5:20).
John shows in this letter how that eternal life works in you as a believer. In order 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 finds itself within you. Therefore it could not be any other way than that it reveals itself in the same way in your life.
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 ascertain and hold on to 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 do a research on water, that is if you want to know what it consists of, then you should not do a research on coffee. Coffee indeed consists nearly one hundred percent of water, but it contains elements that change the taste and color of the water and thereby it is not one hundred percent water. You ought to take pure water in order 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 intensely about that, 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.