John 1.18 notes - Discovery Website

1    Irenaeus, Adv. Haer. 4: 20; Clement, Strom. 5: 12; Origen, Contra Celsum, 7: 43.

2    There is, however, no possible justification for the distinction between ‘God’ and ‘god’ that we find in the New World Translation’s rendering of this verse (‘No man has seen God at any time; the only-begotten god ... has explained him’), given that both appearances of theos here lack the article.