There is one Spirit (Ephesians 4:4) who is God (John 4:23-24).
God the Father, in descending into time to take on an added nature of human flesh, did not VACATE ETERNITY.
So, when He ascended after having descended, He ascended to exist side-by-side with His pre-incarnate form; as He ascended also to fill all things (Ephesians 4:10) and thus in ascending He ascended to inhabit eternity (Isaiah 57:15) once again, as a Spirit (even the same Spirit, Ephesians 4:4)) existing side-by-side with His pre-incarnate Spirit form (even the same Spirit).
Thus, in the beginning was the Word, and the Word was with God, and the Word was God (John 1:1).
And yet, there is absolutely ONE God (James 2:19).