Saint Basil the Great

The Godhead is common; the fatherhood particular. We must therefore combine the two and say, 'I believe in God the Father.'

The like course must be pursued in the confession of the Son; we must combine the particular with the common and say 'I believe in God the Son,' so in the case of the Holy Ghost we must make our utterance conform to the appellation and say 'in God the Holy Ghost.'

Hence it results that there is a satisfactory preservation of the unity by the confession of the one Godhead, while in the distinction of the individual properties regarded in each there is the confession of the peculiar properties of the Persons.

-- Saint Basil the Great