I John 5:9 “If we receive the witness of men, the witness of God is greater: for this is the witness of God which he hath testified of his Son.”
The truth concerning Jesus Christ, the Son of God is so vital to us that God does not rely upon “the witness of men” to communicate it to us. He doesn’t even rely upon the Gospel Preached by men. Our God “the Father, the Word, and the Holy Ghost” is His own “record [“witness”] in heaven” (I John 5:7) and He provides His own “witness in earth” via “the Spirit, and the water, and the blood” (I John 5:8). He testifies of Himself, directly from Himself into the hearts and minds of His “chosen” (Ephesians 1:4) people. The true “witness of men”, via experience’s personal testimony and the Preached Gospel, harmonizes with the “witness of God” that is already in the hearts and minds of the Children of God. And it Assures, Comforts, Exhorts, Encourages, and Motivates them in their life of Service to our Lord. Man is not perfect, but God is; thus, His “witness” is perfect and sure within us!