In the World, Not of It
John 17, Christ's prayer for His people, as the early church lived it
On the night before He died, Jesus prayed for His own: "they are not of the world, even as I am not of the world. I pray not that thou shouldest take them out of the world, but that thou shouldest keep them from the evil." Not removed, not assimilated, but kept, sent. One of the earliest and loveliest of all Christian writings, the anonymous Epistle to Diognetus (around AD 130), describes what that looked like on the ground: believers indistinguishable from their neighbors in dress and speech, yet living as citizens of heaven, "the soul of the world." Its words below, with a plain restatement.
The source's words are verbatim and attributed (the Epistle to Diognetus, an anonymous early apology, in the Ante-Nicene Fathers, public domain; selected from the running prose, footnote apparatus omitted). The box marked "In plain terms" is our own restatement, never the source's words.
John 17:14-16 · KJV…the world hath hated them, because they are not of the world, even as I am not of the world. I pray not that thou shouldest take them out of the world, but that thou shouldest keep them from the evil.
"They dwell in their own countries, but simply as sojourners. As citizens, they share in all things with others, and yet endure all things as if foreigners. Every foreign land is to them as their native country, and every land of their birth as a land of strangers… They are in the flesh, but they do not live after the flesh. They pass their days on earth, but they are citizens of heaven."
The Epistle to DiognetusThis is "in the world, not of it" made visible. The early Christians did not flee society or form a separate tribe; they "share in all things," wear the same clothes, eat the same food, keep the local customs. Yet they hold it all loosely, "as sojourners," because their true citizenship is elsewhere. Every country is home and no country is home; they are "in the flesh, but do not live after the flesh." The dual citizenship Christ prayed for is not retreat and not assimilation, but a settled belonging to heaven while fully present on earth.
John 17:15 · with Matthew 5:44"…keep them from the evil." — "Love your enemies, bless them that curse you… and pray for them which despitefully use you, and persecute you."
"They love all men, and are persecuted by all… They are poor, yet make many rich… they are dishonoured, and yet in their very dishonour are glorified… they are reviled, and bless; they are insulted, and repay the insult with honour; they do good, yet are punished as evil-doers. When punished, they rejoice as if quickened into life."
The Epistle to DiognetusThe shape of this distinct life is the shape of the cross: not power but blessing-under-persecution. "They are reviled, and bless; they are insulted, and repay the insult with honour." It is exactly the upside-down kingdom Jesus described, loving enemies, rejoicing when wronged, rich while poor. What set the Christians apart was not withdrawal or hostility but an inexplicable love that returned good for evil, so that even their persecutors "were unable to assign any reason for their hatred."
Matthew 5:13-14 · with John 17:18Ye are the salt of the earth… Ye are the light of the world. — "As thou hast sent me into the world, even so have I also sent them into the world."
"To sum up all in one word, what the soul is in the body, that are Christians in the world… The soul dwells in the body, yet is not of the body; and Christians dwell in the world, yet are not of the world… Christians are confined in the world as in a prison, and yet they are the preservers of the world. God has assigned them this illustrious position, which it were unlawful for them to forsake."
The Epistle to DiognetusHere is the whole vision in a phrase: "what the soul is in the body, that are Christians in the world." As the soul is spread through every limb yet belongs to a higher order, so believers are scattered through every city as its hidden life. They are "the preservers of the world", its salt and light, the reason it has not yet rotted away. And the post is not optional: God "has assigned them this illustrious position, which it were unlawful for them to forsake." To abandon the world, or to be swallowed by it, is to abandon the calling.
Where this stands among the traditions
The calling to be "in the world, not of it" is cherished by every Christian tradition, and the Epistle to Diognetus is treasured by all as one of the purest early statements of it. The disagreement is never over the principle but over the posture, how to live it out, and the church has long held three options in tension. There is withdrawal (the monastic impulse, and in our day the "Benedict Option"), forming distinct communities to keep the faith pure; there is engagement and transformation, seeking to be salt and light within the institutions of society; and there is the failure mode of accommodation, where the church simply blends in and loses its savor. Diognetus models neither retreat nor surrender but faithful presence: ordinary lives, fully shared with neighbors, yet refusing the culture's sins (the letter pointedly notes Christians "do not destroy their offspring") and returning love for hatred. The drift to resist runs both directions. A church so "of the world" that its loves, ethics, and fears are indistinguishable from everyone else's is salt that has lost its taste. A church so "out of the world" that it abandons its neighbors forfeits its post as the world's preserving soul. The old answer is the hard, beautiful middle: be the soul of the world, wholly present, wholly distinct. (See not everyone who says Lord, faithful unto death, and the letter on what matters most.)
Text from the Epistle to Diognetus (chapters 5-6), an anonymous early Christian apology (c. AD 130), in the Ante-Nicene Fathers (public domain), selected from the running prose with footnote apparatus omitted; nothing added or paraphrased within the quotation marks. Scripture in the King James Version; the plain-language lines are our own restatement. This passage in the Study Bible; John 17 at BibleHub.