The pattern of the Three in heaven bears witness to that triune nature of God.
There is always someone who is the disputer of these things. But I listen to the scriptures.
1 John 5
Whoever believes that Jesus is the Christ is born of God, and everyone who loves Him who begot also loves him who is begotten of Him. 2 By this we know that we love the children of God, when we love God and keep His commandments. 3 For this is the love of God, that we keep His commandments. And His commandments are not burdensome. 4 For whatever is born of God overcomes the world. And this is the victory that has overcome the world—[
a]our faith. 5 Who is he who overcomes the world, but he who believes that Jesus is the Son of God?
The Certainty of God’s Witness
6 This is He who came by water and blood—Jesus Christ; not only by water, but by water and blood. And it is the Spirit who bears witness, because the Spirit is truth.
7 For there are three that bear witness [b]in heaven: the Father, the Word, and the Holy Spirit; and these three are one.
8 And there are three that bear witness on earth: the Spirit, the water, and the blood; and these three agree as one.
9 If we receive the witness of men, the witness of God is greater; for this is the witness of [
c]God which He has testified of His Son.
10 He who believes in the Son of God has the witness in himself; he who does not believe God has made Him a liar, because he has not believed the testimony that God has given of His Son.
11 And this is the testimony: that God has given us eternal life, and this life is in His Son.
12 He who has the Son has [
d]life; he who does not have the Son of God does not have life.
13
These things I have written to you who believe in the name of the Son of God, that you may know that you have eternal life, [e]and that you may continue to believe in the name of the Son of God.