1 John 5:9-12
9 We accept human testimony, but God’s testimony is greater because it is the testimony of God, which he has given about his Son. 10 Whoever believes in the Son of God accepts this testimony. Whoever does not believe God has made him out to be a liar, because they have not believed the testimony God has given about his Son. 11 And this is the testimony: God has given us eternal life, and this life is in his Son. 12 Whoever has the Son has life; whoever does not have the Son of God does not have life.
A Trinitarian friend had made the following remark on the above passage:
"The verse is not to convince that we do away with the Father. It is a message from the Father Himself that we focus on the Son . . ."
(His remark was followed by a string of other verses typically used to support the doctrine of the Trinity.)
My reply:
Yes, the words in 1 John 5:9-12 does bring our focus about "His" Son, rather than "the" Son as you have put it.
Keeping the pronoun "His" in mind, and I shall come back to it at the end of this explanation, let us ask a few simple, direct and explicit questions :
Q1. Whose testimony is greater than human testimony?
Answer: God's testimony. Please note that it is the testimony of our God, not just a "person" within a tri-une "God-head", but instead it is OUR one and only true God who makes His testimony.
Q2. Of whom does God testify?
Answer: God testifies of His Son. Yes, God testifies about His Only Begotten Son, not just "The Father testifies about the Son", but instead it is our God, our only true God, who testifies about His Son.
When Peter was asked by God's Son, "Who do you think I am?", he replied with absolute certainty, "You are the Anointed One (Messiah, Christos), the SON OF THE LIVING GOD". (Matt.16:16)
Dear brother, this is THE GOD who has testified. He is the only true God. And He has testified about His Son, our Master, the Messiah. Do you believe that your GOD has testified? If not, beware lest you be found a liar, as you have not believed the testimony of GOD.
Q3. Finally, what is God's testimony about?
Answer: The testimony says, "God has given us eternal life, and this life is in his Son." Please note carefully, our GOD has given us eternal life. Once again, at risk of being superfluous, I'd like to quote John 17:3 which you have read several times from my previous comments:
John 17:3
Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent.
This is what 1 John 5:9-12 is trying to tell us.
In closing, I'd like to invite you to ponder over the pronoun "His".
Who is this person? Is he just part of a 3-in-1 substance called the "God-head"? Or is he actually our only true God? It is crucial that we get this right, otherwise we may be found to be among the liars mentioned in 1 John 5:10.