⁹If we receive the testimony of men, the testimony of God is greater; for the testimony of God is this, that He has testified concerning His Son. ¹⁰The one who believes in the Son of God has the testimony in himself; the one who does not believe God has made Him a liar, because he has not believed in the testimony that God has given concerning His Son.

We now come to the core teaching of the Christian faith, that Jesus Christ is the Son of God who came in the flesh. Is it really true? If not, then all of Christianity becomes just one religion among many. Even worse, if Jesus Christ is not God in the flesh, then all of Christianity, which purports to be the greatest moral system the world has ever known, is built on a lie. The apostles testified to what they saw and heard; they were willing to die rather than recant their testimony. The record of their testimony is historically credible and convincing. Those who heard the apostles were convinced by their testimony and were also willing to risk their lives for belief in Jesus Christ.

As with all historical records, though, we must rely on biblical scholars to determine the credibility of the research into these matters that happened two thousand years ago, which few of us are able to carry out ourselves. Skepticism reigns in the world, and even creeps into believers’ minds. How can we really know for sure that Jesus is the Christ, the Son of God who came in the flesh?

John, who gave us his eyewitness account (see 1 John 1:1–4 and the gospel of John), tells us there is a “greater” testimony, namely, God’s own personal testimony about His Son. At this point, John moves our thinking from the physical, tangible evidence to the inner, spiritual verification. To today’s scientific mindset, this sounds utterly subjective and places the discussion in the realm of “religious” truth, which is not as “real” as physical reality. But to the believer, the truth of God’s testimony is compelling. The believer can say, “I know it is true because God testifies within me that it is true.”

No one on the outside of me can verify that for me. Only I can be convinced about what God is testifying in me. Every believer can say that; every believer should be able to say that! That is the assurance John is bringing us to in this chapter. We as believers know Jesus is the Son of God come in the flesh because God has made this known to us about His Son. To deny this is to say God is lying, which is impossible (Heb. 6:18).

So, we have two incredible, convincing testimonies about Jesus Christ: the historical apostolic witness and the testimony of God Himself. We have the earthly testimony and the spiritual testimony, appealing to our minds and spirits.

Lord Jesus Christ, I am convinced by the Spirit that You are God incarnate.