This is he who came by water and blood - Jesus Christ; not by the water only but by the water and the blood. And the Spirit is the one who testifies, because the Spirit is the truth. For there are three that testify: the Spirit and the water and the blood; and these three agree.This passage is difficult to interpret because we're not totally sure what is being referred to by the references to the Spirit, the water, and the blood. Interestingly, we can assume that John's original readers knew exactly what he was talking about, because John takes not time to explain it to them. He knew that they knew what he was referring to, so he didn't comment on it further. But alas, we are separated from John and his readers by approximately 21 centuries, so the meaning is a bit more obscure to us. Also, John says that these three witnesses are testifying to something - to what? And how? There are two main ways of thinking about how to interpret this passage. I'll cover each of them, and tell you which interpretation I prefer.
1. The first interpretation states that the Spirit, water, and blood refer to the ongoing testimony evident in the regular Christian life. As a Christian walks with God, there are witnesses that testify to his or her standing as being a child of God. These witnesses are: 1) The Spirit. The Holy Spirit indwells those who are trusting in Christ and empowers them to be able to increasingly throw off the weight of sin and become more and more like Jesus. Moreover, the Spirit provides believers with an "inner-witness" to those who are in Christ that they belong to God. 2) The Water. This interpretation would assert that the witness of the water refers to the declaration of faith made in believer's baptism. When a believer undergoes baptism, he or she is making a public declaration of faith in Christ and intent to follow him all of his or her days. Thus, a believer can look upon his or her baptism as a witness that testifies to his or her standing in Christ. 3) The Blood. Those who adhere to this interpretation regard the witness of the blood as the regular process of observing communion with the gathered church. By taking communion, believers celebrate what Christ has done on their behalf, and participate in the process of working out their salvation with fear and trembling.
Thus, this interpretation finds these witnesses to be a regular part of the Christian life - "the proof is in the pudding," so to speak, as believers testify to their standing as children of God through simply living life and living out their faith in Christ. Through these witnesses, believers can have the assurance they need to overcome the world by faith (1 John 5.4-5).
2. A second interpretation asserts that the three witnesses of the Spirit, water, and blood refer to historical realities rather than to experiential instances. They are as follows: 1) The Spirit: the witness of the Spirit refers to the presence of the Holy Spirit in the life and ministry of Jesus. The Spirit's work through Christ testifies of his divine Sonship. Thus, we are able to know that Jesus is the Christ because of the evidence of his works in the Spirit. 2) The Water. This interpretation asserts that the water refers to the testimony of Jesus being the Son of God that was given at his baptism. When Jesus was baptized the heavens opened up, the Spirit came down on him in the form of a dove, and a voice from heaven declared: "This is my beloved Son, with whom I am well pleased" (Matthew 3.17). 3) The Blood. The testimony of the blood is observed through Jesus' sacrificial death, showing how his divine blood covered the sins of all who would believe for all eternity. The ability of Jesus' blood to atone for sins proves his divinity. This is no mere man, but the Son of God, because only the blood of the Son of God could atone for sin.
And so, this second interpretation seeks to give assurance to Christians that their faith will overcome the world because of the historical reality of of who and what Jesus is, and what he did in his earthly life. These witnesses provide believers with a solid foundation upon which they can build their world-overcoming faith.
Of these two interpretations, I find the latter to be more likely. Although there are several reasons why the second interpretation might be more preferable, the main reason I prefer the second interpretation is contextual. In other words, it seems to work better with the surrounding texts and the overall message of the book of 1 John. One of John's purposes in 1 John 5 is to assure his readers of their ability to persevere throughout all of the difficult situations in which they find themselves: persecution, false teaching, cultural pressure from an unbelieving world, etc. In order for them to persevere through these difficulties, John tells them that their faith is what will give them the victory. But faith in what? In the historical reality of Jesus Christ, the Son of God. John's readers certainly wanted to overcome the world by faith, but perhaps they were unsure how, or if the one in whom they were believing was true. "Yes, he is true," John seems to be saying, "And I'll give you three pieces of evidence."
John identifies faith in Jesus as the Son of God as being the key ingredient for a persevering, overcoming faith. And to bolster their faith, John provides them with three historical witnesses of Jesus' divinity: his anointing with the Holy Spirit (in other words, his miraculous works), his baptism, and his death. Rather than refer his readers to subjective, experiential witnesses like their own baptism and the taking of communion (as discussed in the first interpretation) which are subjective and almost impossible to judge, John gives them an objective rock upon which to anchor their faith: historical reality. By doing so, John effectively tells his readers that they can be absolutely certain that Jesus was the Son of God. And if they can be certain of that, then they should believe it. And if they will believe it with certainty, this faith will give them victory over the difficulties faced in life as a product of living in a fallen world.
While faith in a person or thing is never conclusive, it is simultaneously based on evidence. John is saying that the evidence presented by the witnesses of the Spirit, the water, and the blood that Jesus is the Son of God is overwhelming, and is worthy of being believed. Like John's original readers, we can be certain of the witness of the Spirit, the water, and the blood. The evidence point to the authenticity of the object of our faith (Jesus, the Son of God) is overwhelming. Moreover, we have the guarantee of God himself about who Jesus is and what he has done (see 1 John 5.9) And therefore, our faith in him is not in vain. Rather, it is empowering us to the extent that it will carry us through the challenges presented to us in life until the day of our death. Through faith in Christ we are more than conquerors through him who loved us. For we are sure that neither death nor life, nor angles nor rulers, nor things present nor things to come, nor powers, nor height nor depth, nor anything else in all creation will be able to separate us from the love of god in Christ Jesus our Lord (Romans 8.37-39).