Where did you get this information concerning the old writings?
Plus in reading what is written there in the first ones, they do not prove that God is three persons as I see it at all.
What they do prove, in particular, what Barnabus wrote, is God certainly has manifested Himself in three different ways.
But if one is willing to look at what you believe compared to what I and many others like me that do see God as being on Spirit only do believe, that there is not a whole lot of differences between this belief.
Although I also know that often in telling either side that believe this has to be seen to be saved, is frivolous on my part, both sides raising a great big stink whenever I have suggested such a possibility.
I did not get very far in it though, as I am mainly interested in what the original apostles and prophets believed also. Which is why I mentioned what I saw as Barnabus saying. My seeing he could just as easily be saying what I see, as much as what you do. Because most would never deny that God has come to us in three different ways, those ways being as Father, Son and Holy Ghost in order to restore mankind to Himself.
But I am sure you copied from somewhere, and was wondering where you did get it from?
FOR THE LORD SAID UNTO SAMUEL, LOOK NOT ON HIS COUNTENANCE OR ON THE HEIGHT OF HIS STATURE, BECAUSE I HAVE REFUSED HIM: FOR THE LORD SEETH NOT AS MAN SEETH: FOR MAN LOOKETH ON THE OUTWARD APPEARANCE; BUT THE LORD LOOKETH ON THE HEART. (1 Sam. 16:7)