Ye know that the only-begotten Son is called the Word of the Father. Now we know, in the case of our own utterance, the voice first sounds, and then the word is heard. Thus John declares himself to be the voice, i. e. because he precedes the Word, and, through his ministry, the Word of the Father is heard by man.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. vii. c. 2