As indicated in the footnote of Good News Translation, this verse presents the same textual problem as verse 11.
Except for the change of the imperative (keep them safe) to the indicative (I kept them safe), the first sentence of this verse repeats the thoughts of verse 11. I kept them safe by the power of your name, the name you gave me may be rendered “I kept them safe by your power, the power you gave me.”
The verb protected is the same one rendered keep in 12.25 and obey in 12.47, the only other two occurrences of the verb in John’s Gospel. Ordinarily protected would be considered a stronger term than keep … safe, but in the present context the two verbs are used synonymously, one reinforcing the other. The use of synonyms is characteristic of the Johannine style.
Was lost is the same verb rendered die in 3.16 and 10.28; in 12.25 it is used with the same meaning it has here. Because of the continuing relationship of Judas Iscariot to the developments described in Chapter 18, it may be necessary in some languages to use the perfect tense here, for example, “not one of them has been lost.”
The man who was bound to be lost (New American Bible “him who was destined to be lost”; New English Bible “the man who must be lost”; Jerusalem Bible “the one who chose to be lost”; Goodspeed “the one who was destined to be lost”) has been traditionally rendered “the son of perdition.” The word rendered “perdition” in many translations is a noun made from the same stem as the verb translated was lost in Good News Translation and most other translations. This word is frequently used in the New Testament of the final fate of those who are without God (see Matt 7.13; Acts 8.20; Rom 9.22; Phil 1.28; 3.19; 1 Tim 6.9; Heb 10.39; 2 Peter 2.1; 3.7; Rev 17.8,11). The phrase “son of (literally “man of”) perdition” means “one who is going to be lost (eternally).” The same expression appears in Thessalonians 2.3 and is rendered the … One … who is destined to hell in Good News Translation.
In English the form lost fits very well into this type of context, but in other languages a literal rendering may be misleading, since it might suggest that in some way or other Jesus had lost sight of Judas. A more appropriate equivalent in some languages is “has gone astray” or “has suffered ruin.” Accordingly, the phrase the man who was bound to be lost may be rendered “the man who would certainly go astray” or “the man for whom there was nothing else but to suffer ruin.”
That the scripture might come true is best taken as a reference to Psalm 41.10, referred to in 13.18. To show the relation of the clause that the scripture might come true to what has preceded, it may be necessary to add such a phrase as “all this had to happen so that the scripture might come true” or “… so that what is written in the scripture would prove to be true” or “… would tell it as it really turned out to be.”
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 .