In verse 20 John also says that we are in the true One. We not only know the true God; we are also in Him. We not only have the knowledge of Him; we are in an organic union with Him. We are one with Him organically.
When John says that we are in the true One, he is making a crucial point. Not only do we know the true One and experience, enjoy, and possess Him as the reality, but we also are in this reality. We are in the true One.
John tells us that we are “in Him who is true, in His Son Jesus Christ” (v. 20). To be in the true God is to be in His Son Jesus Christ. Since Jesus Christ as the Son of God is the embodiment of God (Col. 2:9), to be in Him is to be in the true God. This indicates that Jesus Christ the Son of God is the true God.
Being in the true One is equal to being in His Son Jesus Christ. This indicates that the true One and Jesus Christ are one in the way of coinherence. Therefore, to be in the Son is spontaneously to be in the true One. Furthermore, we are in the true One by virtue of being in His Son Jesus Christ.
The last part of 1 John 5:20 says, “This is the true God and eternal life.” The word this refers to the God who has come through incarnation and has given us the ability to know Him as the genuine God and be one with Him organically in His Son Jesus Christ. All this is the genuine and real God and eternal life to us. This genuine and real God is eternal life to us so that we may partake of Him as everything for our regenerated being.
We need to pay special attention to the word this. In verse 20 John does not say “He is”; he says “this is.” Furthermore, John uses the word this to refer both to the true God and to eternal life. By this we see that the true God and eternal life are one.
We have seen that we are in the true One and in His Son Jesus Christ. Doctrinally, the true One and His Son Jesus Christ may be considered two. But when we are in the true One and in Jesus Christ experientially, these two are one. For this reason John uses this to refer both to the true One and to His Son Jesus Christ.
We have seen that to be in the true One is to be in His Son Jesus Christ. This means that in our experience of being in Them, They are one.
Moreover, when we are in the true One and Jesus Christ, They are our true God and also our eternal life. John speaks first of the true One and His Son Jesus Christ, and then he speaks of the true God. Here there may be some distinction between the true One and the true God. When we are in the true One and His Son Jesus Christ, the true One is called the true God, and His Son Jesus Christ is called eternal life. This means that first They are the true One and His Son Jesus Christ. But when we are in Them, They become the true God and eternal life.
The word this in verse 20 refers to the God who has become experiential to us through our being in Him. No longer are we outside of this God. Rather, we are in this God, and we are in the true One, in His Son Jesus Christ. Because we are in Them, God and Jesus Christ are no longer objective to us, and in our experience They are no longer two. When we are in Them, They become one to us. Therefore, John says that “this” is the true God, and “this” is eternal life. “This” is the God and the Jesus Christ in whom we are. We may also say that “this” includes the condition of our being in God and Jesus Christ. Hence, the true God and eternal life include our being in the true One and His Son Jesus Christ.
If we are not in God, we cannot say from experience that to us He is true. Of course, He would still be true in Himself, but we could not testify that in us He is true. But since we are in the true One, to us He is the true God. Furthermore, Christ is eternal life to us. If we were not in Him, Christ would still be eternal life in Himself, but He would not be eternal life to us. Because we are now in Him, to us Jesus Christ is eternal life.
In verse 20 we have the crucial conclusion of the entire Epistle of 1 John. This Epistle reveals that now we are truly one with the Triune God, and He becomes true, real, to us. He becomes reality and life to us because we are in Him.
The word this in verse 20 implies that God, Jesus Christ, and eternal life are one. In doctrine, there may be a distinction between God, Christ, and eternal life, but in our experience they are one. When we are in God and in Jesus Christ and when we experience eternal life, we find that all these are one. Therefore, John concludes verse 20 by saying, “This is the true God and eternal life.”
In verse 21 John goes on to say, “Little children, guard yourselves from idols.” The word guard means to garrison ourselves against attacks from without, like the assaults of the heresies. Idols refers to the heretical substitutes, brought in by the Gnostics and Cerinthians, for the true God, as revealed in this Epistle and in John’s Gospel and referred to in the preceding verse. Idols here also refer to anything that replaces the real God. As genuine children of the genuine God, we should be on the alert to guard ourselves from these heretical substitutes and all vain replacements for our genuine and real God, with whom we are organically one and who is eternal life to us. According to John’s understanding, an idol is anything that replaces, is a substitute for, the subjective God, the God whom we have experienced and whom we are still experiencing. This is the aged apostle’s word of warning to all his little children as a conclusion of his Epistle.
Anything that is a substitute or replacement for the true God and eternal life is an idol. We need to live, walk, and have our being in this God and in this life. Unless we live in the true God and eternal life, we will have a substitute for the true God, and this substitute will be an idol.