But he (Stephen)
full of the HOLY SPIRIT, gazed into heaven
and saw the glory of GOD,
and JESUS standing at the right hand of GOD.
and he said,
"Behold, I see the heavens opened,
and the Son of Man standing at the right hand of GOD."
Notice Stephen is full of the Holy Spirit, Jesus is standing at God's right hand. All three are independently mentioned at the same time... Here you see a clear picture of the three persons of the Trinity, yet brining in Deut. helps to balance this. Three persons who are one, just like the old creeds of the Church confessed. Coming from a oneness background who only believed in different modes of God: Father, Son and H.S. they were all the same just different manifestations of God (like an actor putting on a different costume). Yet this chapter in the book of acts wont allow for it. You see Three at the same time.
A Theologians job isn't to make up ideas, their job is to explain what they read in the scriptures. "I see three persons in the one God." this isn't something man made, and godly men of old grappled with the text to fit the revelation of God in the O.T. with the further revelation of God in the N.T.