I am completely stymied on finding an origin for the common phrase stating that Christians ought to be “in the world but not of it.” Yes, of course there are biblical roots for the idea, notably John 17:15 & 16, where Jesus says that He is not asking the Father to take His followers out of the world, but that, like He Himself, they do not belong to the world. At some point in history, that prayer of the Lord, perhaps echoed in other New Testament passages about not loving the world and the things in it, became encapsulated in the slogan, “Be in the world but not of it.”
So our Gospel text for this Sunday, Matthew 5:13-20, seems like an excellent excuse, as good as any, for considering that phrase “in but not of” and what it means for Christian living. Jesus’ homely images of salt and light offer not just a negative interpretation of what it means to be “in but not of,” i.e., things like abstinence from the sins of the world or non-participation in worldly distractions. Being salt and light suggests that Christians live in ways that are visibly different from the ways of others, the ways of the world, and are positively attractive when doing so.
Here’s a quote from a second century Christian epistle, The Letter to Diognetus, which nicely captures an early grasp of the attractiveness of the Christian manner of life:
“Christians are indistinguishable from other men either by nationality, language or customs. They do not inhabit separate cities of their own, or speak a strange dialect, or follow some outlandish way of life. Their teaching is not based upon reveries inspired by the curiosity of men. Unlike some other people, they champion no purely human doctrine. With regard to dress, food and manner of life in general, they follow the customs of whatever city they happen to be living in, whether it is Greek or foreign.
And yet there is something extraordinary about their lives. They live in their own countries as though they were only passing through. They play their full role as citizens, but labor under all the disabilities of aliens. Any country can be their homeland, but for them their homeland, wherever it may be, is a foreign country. Like others, they marry and have children, but they do not expose them. They share their meals, but not their wives.
They live in the flesh, but they are not governed by the desires of the flesh. They pass their days upon earth, but they are citizens of heaven. Obedient to the laws, they yet live on a level that transcends the law. Christians love all men, but all men persecute them. Condemned because they are not understood, they are put to death, but raised to life again. They live in poverty, but enrich many; they are totally destitute, but possess an abundance of everything. They suffer dishonor, but that is their glory. They are defamed, but vindicated. A blessing is their answer to abuse, deference their response to insult. For the good they do they receive the punishment of malefactors, but even then they, rejoice, as though receiving the gift of life.”
What can we learn from that second century understanding of what it means to be salt and light, or to be “in the world but not of it?” Much, I think.