I believe "Jesus is God" AND "God is Jesus" because...
If you define "is" as "
selfsame", then "Jesus is God" and "God is Jesus" would both be True, since "Jesus" and "God" are the same "thing".
And if you define "is" as "
homegeneous", then "Jesus is God" and "God is Jesus" would both be True, since "Jesus" and "God" have the same "nature".
But what is the Trinitarian definition of "is" such that "Jesus is God" is True, but "God is Jesus" is False?
Aside from the semantics used to define God...
There are three aspects of God, and they can't be defined in terms of the limitations used to define humans. God is the father, Jesus is the son, and the Holy Spirit is, well, the spirit.
Even though I am vigorously opposed to Donald Trump I will use the US government as an example. If the President sends the Secretary of State abroad, s/he fully represents the US. When Jesus became a human being he fully represented his father -- "I can do nothing apart from the Father". He was not equal to his father, but was his son who fully represented him on earth. 1 Corinthians explains it best, "Then comes the end, when he [Jesus] hands over the kingdom to God the Father, when he has brought to an end all rule and all authority and power. For he must reign until he has put all his enemies under his feet. The last enemy to be eliminated is death... And when all things are subjected to him, then the Son himself will be subjected to the one who subjected everything to him, so that God may be all in all." Clearly they are two separate people, with the father having authority over his son. (This was normal in biblical times. It was unthinkable for a son to be equal to his father.)
Now when Jesus was resurrected did that leave humans without a divine presence? No. People were given the Holy Spirit, God's spirit, to live in them. God didn't just send Jesus and that was that. Continuing the analogy, when the Secretary of State signs a treaty and leaves, the treaty -- the presence of the United States -- remains in effect and there is an ambassador to represent the country. Christians are one with Christ; we are his presence on earth. Even though Jesus, God's representative, isn't present, we have been given his spirit; we are God's ambassadors on earth. We represent his kingdom.
I have not been able to come up with a better analogy to explain God the father, Jesus the son, and the Holy Spirit. They are all different, yet they are all one. They have different roles and authority, but together they are God.