Here’s the way I look at the Trinity:
God the Father is the great “I am”, creator, sustainer and maintainer of all that exists. Jesus Christ the Son of God is “the image of the invisible God” (COL 1:15), or the “Word made flesh” that dwelt among us” (JOHN 1:14) in our space-time. The Holy Sprit is God’s presence and the agent of His will in our space-time. Note that He (the Spirit) “beareth witness, because the Spirit is truth” (1JOHN 5). One God, three manifestations.
As a point of interest, in Matt 3:16,17, all three elements of the Trinity were present and monifested in our space-time at Jesus’ baptism: “16 And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:
17 And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased”.
This is as much as my finite mind can grasp of what the Scrpture has to say about the Trinity. Your comments are welcome.
I am putting together a Scriptural Rosary for Priests and I included that quote — only from the RSV in it.