1 John 5:20 20And we know that the Son of God has come and has given us understanding, so that we may know the true one, and we are in the true one, in his Son Jesus Christ. This one is the true God and eternal life.
The final assurance that we know focuses on the true story of redemption in Jesus Christ, the Son of God. This verse makes several important assertions. The first essential truth is that Jesus has come in the flesh (4:2). The historical fact of Jesus’ existence grounds Christianity in reality rather than myth. The crucial matter of faith is to believe that Jesus was a real person. This tenet is important because the whole doctrine of salvation rests on the reality of Jesus’ physical death and resurrection.
Second, Jesus has revealed the Father and helped humanity better understand God. Understanding (dianoian)refers to the ability to reason and consider carefully. Sin corrupts and subverts the reasoning powers by warping the will (Ephesians 4:17, 18, 23). By knowing Jesus, we know the Father. By gaining an intimate union with Jesus, we also gain union with God the Father. From this relationship flows all of Christian doctrine and experience. The theme of abiding in God or in Jesus is an important theme in John’s Gospel and this letter (4:15, 16, 12).
Third, the result of this new relationship is a personal knowledge of God, not just knowing about God. A person can study theology and even earn high academic degrees in it. But the person with simple but dedicated faith can know God personally and experientially. This living knowledge leads to the assurance of faith. Because we are far removed from the historical Jesus by over two thousand years, culture, and language, we must trust in the truth and validity of the testimony found in the New Testament.
This verse has one translation issue about the identity of the true one. The word is a substantival masculine adjective, leaving the options either as God the Father or Jesus the Son. Either option fits the verse. The grammatical issue leads to the theological issue of the identity of the true one in the last clause as the true God. Jesus perfectly represented God, so the adjective could refer to him. Jesus came and revealed God’s nature of love. We know God through Jesus Christ, who fulfilled and confirmed all Old Testament prophecy and revelation. Jesus came so that we might come to know God. Before Jesus, Israel had knowledge of God, but this was mediated through priests and scribes. Some people had deep, personal knowledge of God, but the problem of sin kept most people away. They could not overcome sin through their own efforts to keep the law, of which they had limited knowledge anyway. When Jesus came, he embodied and fulfilled the heart of the law, which is love. He came as the Way, the Truth, and the Life so that we might know God.
The result of knowing him is eternal life. John may have been reflecting on how this knowledge of God was the fulfillment of Jesus’ prayer in John 17:3. The letter ends like it begins with its claim about Jesus in 1:2: he is the one who has eternal life. When seen from the vantage of this verse, the mysteries of life begin to make sense. We come to know God and God’s purposes for us. We have the assurance of eternal life after we die and the experience of transformation in this lifetime.