We are often reminded that as Christians we are to be “in” the world but not “of” the world. Here the term “world” is used equivocally, for we are “in” the world as the place of God’s creation where we dwell and experience life, but we are not supposed to be “of” the world—the world in this sense being the arena of apostasy, everything in the world that is not of God or is set against Him, the degeneracy of certain elements of our culture, etc. This idea has been taken, at least in part, from Jesus’ high-priestly prayer to the Father, for his disciples: “I am not praying for the world [in the negative sense]… they are not of the world, even as I am not of the world. I do not pray that you should take them out of the world, but that You should keep them from the evil one” (John 17:9, 14-15). Since He doesn’t ask them to be taken out of the world (the world He has created), they are to be in the world, but He also makes clear that they are not of the world, that is, not belonging to it, not following its godless ways (“I testify of it that its works are evil”; John 7:7).
All this is true, but perhaps does not exhaust the meaning of being in the world and not of it, since it is mainly a negative approach, that is: be not of the world so as to avoid all its evils.
He begins by saying: “Why do you live as if you still belonged to the world?” (Col. 2:20). This presupposes that Christians know who they are, what God has done for them, and what their destiny is. The negative part is that Christians have “died” to the world, that is, have severed their inordinate worldly attachments and have thus become free to focus on divine and eternal matters. Therefore, he says in another place, let “those who deal with the world act as though they had no dealings with it, for the form of this world is passing away. I want you to be free from anxieties” (1Cor. 7:31-32). Again he says that our citizenship is in Heaven, so we ought not get so entangled in the world’s affairs that we lose sight of our reason for being here in the first place. We ought not adopt a “Heaven can wait” attitude while we attempt to make our fortunes here and now.
To be a Christian is to live a radically different form of life than those who are not—though externally it may not at first glance seem so different—but unfortunately the Christian Gospel has become so watered down, so compromised with the world as to seem to require little more than a bit of religious practice pasted onto an otherwise worldly life. But to accept that is to deny true Christianity and Christ as well.
In order to be not “of this world,” we have to be “of God,” of Christ, that is, belonging to the world of the Spirit, of Heaven, of the grace and truth and love of the Lord. We are in this world, which is so often set against God, so as to witness to the real world, the world “hidden with Christ in God,” the world we enter through faith, the sacraments and prayer, and to which we bear witness by the way we live. To be not of this world is not simply to avoid its evils, but to infuse it with good, to help win it back for God, who so loved the world that He gave his only Son to save it.
We can’t help but be in the world as long as we live. But we have a choice about being of the world. Let us make no mistake: to be “of the world” is to be “not of God” (see John 8:23, 47, and James 4:4). And the only thing that matters on Judgment Day—which means the only thing that ultimately matters at all—is to be found to be of God.