New American Bible and certain other translations render this verse literally: “he must increase, while I must decrease.” In the present context the meaning of “increase” is taken to mean become more important, while the meaning of “decrease” is become less important. New English Bible reads “As he grows greater I must grow less,” which is ambiguous. However, the meaning may be “to increase the number of disciples.” If so, one could translate: “He must win more and more followers, while the number of my followers will decrease.”

A literal translation of “He must increase and I must decrease” can be misunderstood, since it may be taken to refer to differences of physical size. As noted in 1.30, greatness must be considered in terms of importance—an interpretation which often leads to metaphorical extensions of meaning.

In this context the auxiliary must may be rendered in some languages as equivalent to “it is inevitable that,” but in other languages the closest equivalent may be “it will surely be.” Must renders a verb commonly used in the New Testament to indicate divine necessity; the same verb is used in verse 14.

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 .