This happened so that the words he had spoken would be fulfilled: “I have not lost one of those you gave me.”
It is common to find in the Bible that something has happened “in order that the scripture might be fulfilled.” John uses that phrase here for the word which Jesus had spoken. It is inconceivable that a word of Christ could possibly fail to be fulfilled. The word referred to is (17:12) which is also in complete accordance with the will of God (6:39). The fulfilling of this word here also indicates that its fuller meaning will also find fulfillment. That “fuller meaning” is that we are included in those the Father has given Him. (John 10:28-29, 1Thess 5:23, 2 Tim 4:17-18) God’s promise was true for them and it is just as true and certain for you.
John 17:12 While I was with them, I protected them and kept them safe by that name you gave me. None has been lost except the one doomed to destruction so that Scripture would be fulfilled.
John 6:39 And this is the will of him who sent me, that I shall lose none of all that he has given me, but raise them up at the last day.
John 10:28-29 I give them eternal life, and they shall never perish; no-one can snatch them out of my hand. My Father, who has given them to me, is greater than all; no-one can snatch them out of my Father’s hand.
1 Thessalonians 5:23 May God himself, the God of peace, sanctify you through and through. May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ.
2 Timothy 4:17-18 But the Lord stood at my side and gave me strength, so that through me the message might be fully proclaimed and all the Gentiles might hear it. And I was delivered from the lion’s mouth. The Lord will rescue me from every evil attack and will bring me safely to his heavenly kingdom. To him be glory for ever and ever. Amen.