John 18:9 - Ellicott's Commentary On The Whole Bible

That the saying might be fulfilled, which he spake. — Comp. John 17:12. The quotation is in many ways suggestive. (1) It is not verbally accurate, i.e., St. John, quoting the words of Christ, which he has himself recorded a few verses before, is at no pains to reproduce it word for word, but is satisfied in giving the substance of it. This throws light on the general literary habits and feelings of this age and race, and it is in full harmony with the usual practice of quotation in the New Testament. (2) St. John quotes with an application to temporal persecution that which had been spoken of spiritual persecution. This illustrates the kind of way in which words are said to be “fulfilled” in more than one sense. Striking words fix themselves in the mind, and an event occurs which illustrates their meaning, and it is said therefore to fulfil them, though of each fulfilment it can be only part. (Comp. especially Notes on John 2:17; John 12:38 et seq.) (3) The quotation shows that in the thought of St. John himself, the prayer recorded in John 17 is no résumé of the words of our Lord, but an actual record of His prayer: he quotes the “saying” as fulfilled, just as he would have quoted a passage from the Old Testament Scriptures.