Commentaries:
The world Jesus speaks of is Satan's anti-God system working in and through men. Within it are the cultures of all nations on earth. Jesus is clearly not of that anti-God system, and He declares that those accompanying Him, the apostles, were not of the world either. They were of the same system as He—the Kingdom of God. The same is true of those in Christ today.
John W. Ritenbaugh
The Offerings of Leviticus (Part Eight): Conclusion (Part One)
Other Forerunner Commentary entries containing John 17:15:
Matthew 6:9-13
Matthew 6:9-13