My prayer is not that you take them out of the world but that you protect them from the evil one (John 17:15).
In this section our Lord indicated the great realm of controversy between Himself and Satan, the realm in which Satan finds his activity manifested–the world. Throughout this whole discourse you find two communities in view: the world, which is secular society organized in its antipathy against God; and the church, the body of Christ, God’s family.
The Lord knew that there would be this conflict. He called a group out of the world–not to be separate from it–but to be a different group. God always sees humanity divided into two categories. Sometimes they are called two kingdoms–the kingdom of God and the kingdom of Satan. Sometimes they are regarded symbolically as two cities–Jerusalem and Babylon. But there are always these two.