The three are one in the sense that they are one in Purpose, but that does not mean that Jesus was God.
I believe that the Father, the Son and the Holy Spirit work together, but they are separate. I do not believe that the three of them were part of One God as the Trinitarians believe.
The Baha’i Faith believes in a Trinity, and the detailed explanation is in this chapter: 27: THE TRINITY
In brief, here is how the Baha’i version of the Trinity operates.
· God is exalted above anything that can ever be recounted or perceived so God remains in His own high place, on His Throne. God never descends to earth.
· God sent Jesus from heaven and Jesus was born of the Holy Spirit from the womb of Mary into a human body
· Later, after Jesus reached a certain age, God sent the Holy Spirit to Him and it descended upon Him like a dove.
The Baptism of Jesus
13 Then Jesus came from Galilee to the Jordan to be baptized by John.
14 But John tried to deter him, saying, “I need to be baptized by you, and do you come to me?”
15 Jesus replied, “Let it be so now; it is proper for us to do this to fulfill all righteousness.” Then John consented.
16 As soon as Jesus was baptized, he went up out of the water. At that moment heaven was opened, and he saw the Spirit of God descending like a dove and alighting on him.
17 And a voice from heaven said, “This is my Son, whom I love; with him I am well pleased.”
After Jesus received the Holy Spirit from God the Father, Jesus brought the Holy Spirit to humanity, and Jesus shed the splendor of His glory upon all created things.
“Know thou that when the Son of Man yielded up His breath to God, the whole creation wept with a great weeping. By sacrificing Himself, however, a fresh capacity was infused into all created things…..
We testify that when He came into the world, He shed the splendor of His glory upon all created things. Through Him the leper recovered from the leprosy of perversity and ignorance. Through Him, the unchaste and wayward were healed. Through His power, born of Almighty God, the eyes of the blind were opened, and the soul of the sinner sanctified.”
Gleanings From the Writings of Bahá’u’lláh, pp. 85-86
It's worth mentioning, as an aside, that 1 John 5:7 is not original to that epistle. It was added centuries later, as an obvious attempt to "write in" more explicit Trinitarian language than exists elsewhere.
Carry on.