Footnote

b Novatian is referring to the fact that the word for “one” in this verse is in the neuter gender. Hence, its natural meaning is “one thing.” Compare John 17:21, where the Greek word for “one” is used in an exactly parallel way. Interestingly, the New Catholic Encyclopedia (1967 edition) generally approves of Novatian’s De Trinitate, although it notes that in it “the Holy Spirit is not considered a divine Person.”