Like many among the nomad generation, I have moved and moved yet again. Across the country and halfway back, from North Carolina to British Columbia to Texas. And in each new place, I find myself asking the same question: How will we ever make friends again?

If we know ourselves through our friends—if our friends, in some sense, make us who we are—then to be uprooted is to lose something of yourself. It is to be torn, to be undone.

This high valuation is not only anecdotal. Ancient and contemporary theorists alike insist that friendship is foundational to human life. If we’re social animals, as Aristotle knew, then friendship is a kind of virtue. Contemporary positive psychologist David Myers labels friendship one of the “deep truths” of happiness. No wonder Augustine, as Peter Brown so memorably put, “will never be alone.”

Lamenting and longing for friendship, we find in Augustine a trustworthy guide. He knew that friendship was a natural good, a pillar of marriage and human society (see, e.g., On the Good of Marriage 1.1). But if he knew its powers for good, he also perceived its potency for vice. Most famous, certainly, is Augustine’s  “inimical friendship” (inimica amicitia) with his Thagaste peers with whom he raided the local pear garden (Conf. 2.9.17). Equally troubling, though infinitely more touching, is his friendship with a young man—we never learn his name—whose death left Augustine completely undone.

Augustine laments how he thought of his friend—in language echoing Horace and Ovid—as “half of his soul;” they were “one soul existing in two bodies” (4.6.11). At one level, it was an error of judgment, a confusion of God and creature: “I had poured out my soul on to the sand by loving a person sure to die as if he would never die” (4.8.13). Augustine considers his life, his work, his city—light itself—an abject horror. It’s at this point he utters for the first time that most paradigmatic of Augustinian confessions: “I have become a great question to myself” (4.4.9).

It would be tempting to conclude, pace Aristotle and positive psychology, that friendship inhibits beatitude. Our deep-set need for friendship tempts us to treat creaturely friends as gods never to die. And when they die—and they always die—a part of us dies, too.

But as the story goes on, we find other friends—named friends—who lead Augustine to Christ. Augustine’s relationships with Alypius, Nebridius, Simplicianus, Ambrose, and even his mother Monica help him to find redemption through a kind of friendship. Already in Book 4, though, Augustine alludes to the difference between virtuous and vicious friendships. “A true friendship,” Augustine writes, “is not possible unless you bond together those who cleave to one another by the love which ‘is poured into our hears by the Holy Spirit who is given to us’” (4.4.7, citing Rom. 5:5). It all hinges on that little preposition “in.” “Happy is the person who loves you and his friend in you” (4.9.14; emphasis added).

If your delight is in souls, love them in God, because they too are frail and stand firm only when they cling to him. If they do not, they go their own way and are lost. Love them, then, in him and draw as many with you to him as you can. Tell them, “He is the one we should love. He made the world and he stays close to it” (4.12.18; emphasis added).

A true friendship is not merely a unity of souls. True friendship is a unity between creatures bound in the love of the Holy Spirit, God’s own agency of union and charity. Such friendships can endure even death, because the one who loves a friend in God, Augustine writes, loves someone who is held in the eternal charity of the Triune God. “Though [a person is] left alone, he loses none dear to him; for all are dear in the one who cannot be lost. Who is that but our God, the God who made heaven and earth and filled them?” (4.9.14).

Far from rejecting one’s friends for God, the one who loves one’s friends in God loves them in such a way that frees them from our demands, our cleaving to them as if they would never die. It liberates them from the tyranny of what Rowan Williams calls “inhuman love”—the temptation to love human beings in a manner unbefitting to human nature. Friendship in God means we no longer demand from friends a happiness they cannot give, since they cannot bear the weight of our loves. God alone can bear such weight, and when we love others within the capacious realm of divine love, it is then, only then, when true friendship becomes possible.