I dedicate … to you is the same verb translated dedicate … to yourself in verse 17. Jesus dedicates himself to the Father so that his disciples might also be dedicated to the Father. I dedicate myself to you may be expressed in some languages as “I give myself to you.” However, in others it may be appropriate to use an expanded phrase, for example, “I give myself to serve you.” The purpose clause may then be expressed as “in order that they also may give themselves to serve you.”

The Greek phrase rendered truly here is literally “in truth,” while by means of the truth in verse 17 is literally “in the truth.” If the phrase “in truth” appeared in isolation, it would be natural to translate it as an adverb (truly). However, in the present context it seems best to understand this phrase as equivalent to the former phrase and so to translate it “by means of the truth.” Modern translations differ here, but some of them do render these two phrases exactly as suggested above. If truly is to be understood adverbially, it may be rendered in some languages “as they ought to,” for example, “that they may give themselves to you as they ought to.” It may also be possible to understand truly in the sense of “completely,” for example, “so that they also may give themselves to you completely.” But if one assumes that the appropriate meaning of truly is “by means of the truth,” the closest equivalent may be “in order that they also may give themselves to you by means of your words, which are true” or “… by means of your true message.”

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 .