Teacher is transliterated as “Rabbi” in most translations. “Rabbi” is, of course, the title given to the Jewish teachers of the Law (see 1.38).

In some languages it is impossible to address a person by a title which identifies his function or profession. For example, one cannot directly address a person as “Teacher.” However, one can introduce this term into the structure of verse 49 by saying “Nathanael replied to Jesus as to a teacher” or “Nathanael addressed Jesus as a teacher and said.”

King of Israel is definitely used as a Messianic title. In 2 Samuel 7.14 and Psalm 2.7 God addresses the Messianic king as “my son.” Since both these term are equally Messianic titles, there is no anticlimax in the present passage which places King of Israel after Son of God. The order is perfectly logical and reflects a definite temporal sequence, for it is only as Jesus is designated the Son of God that he can become the King of Israel in this Messianic sense.

Jesus is once again designated King of Israel in 12.13. In 6.15 the Jews want to make Jesus their king, but he refuses. In Chapters 18–19 Jesus is several times referred to as the king of the Jews. However, there is no indication that Jesus is encouraged the use of this title. All the evidence points to the contrary.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .