In tractate CV of his Tractates on the Gospel of St. John, Augustine changed the text of John 17:3 to include the person of Jesus as being included in "the only true God":
"And this,"
He adds, "is eternal life, that they may know Thee, the only true God, and
Jesus Christ, whom Thou hast sent." The proper order of the words is,
"That they may know Thee and Jesus Christ, whom Thou hast sent, as the
only true God."
The following comes from H.A.G. Houghton
in his book-length study of the text of John in Augustine’s writings:
Most remarkable is
the treatment of John 17:3. Throughout the first half of Book I and all of Book
II, every reminiscence of this verse includes the word solus, either as
unus et solus deus (De trinitate 1.6.9, 1.6.10) or unus et solus
et uerus deus (De trinitate 1.2.4, 1.6.19, cf. 1.6.11). This does
not appear in any of the verbatim citations in the second half of Book I (De
trinitate 1.8.17, 1.13.30, 1.13.31). As Augustine seems to have known two
forms of this verse this (see p. 333) this detail seems to reveal the different
stages of composition. (H.A.G. Houghton, Augustine's Text of John: Patristic
Citations and Latin Gospel Manuscripts [Oxford Early Christian Studies;
Oxford: Oxford University Press, 2008], 154)
John 17:3
Augustine's shorter
references to this verse are of limited textual value and may have been
influenced by credal statements. Nonetheless, it is clear that he knew it in at
least two forms: unum uerum deum, preserved only in Codex Vercellensis,
is found in longer citations and in at least eleven works, including De
trinitate 1, De consenu 3.25.86, and Tractatus 3, 19, 21, and
101. A similar number of writings have the reading of most other gospel
manuscripts, solum uerum deum, including not only the commentaries at Tractatus
105 and 106, but also De diuersis quaestionibus 35.2. Another early work,
De duabus animabus 10, has the form solum et uerum deum, matching
Codices Veronensis, Palatinus, and Monacensis, while Augustine's first two
citations omit the first word completely. The unusual doublet form unus et
solus (et uerus) deus in allusions in later parts of De trinitate 1
and 2 has also been considered above (p. 154). A few citations omit autem
(e.g., De moribus 1.25.47, Sermones 217.1, 362.29.30); although
this is likely to be flattening, it does correspond to a Greek variant. Enim
in Enarratio 86.21 is unique. In his exegesis, Augustine is more concerned
with punctuating or re-ordering the verse to establish the divinity of Christ
than the rendering of μονον (cf. Contra Maximinum 2.15.4 responding to
Maximinus at Collatio cum Maximino 15, Epistula 238.4.22, Sermo
217.1, Tractatus 105.3, De spiritu et littera 22.37). (Ibid.,
332-33)
