He is one. God the Father who rules over heaven, his fleshly body who cane to earth, and his spirit, which makes intercession. Three different planes of existence with one powerful being.
They are all God. It's his three planes of existence so to speak. We call his three planes:
The Father
The Son
The Holy Ghost
it's not literally three people, it's more like the same person but split between three planes. God's holy form is in heaven. His bodily form came to die for our sins. His astral form helps us communicate with him, and is also the part of his spirit that comforts and guides us in this world.
Holy Form
Physical Form
Spiritual Form (as in Spirit)