19th Sunday in Ordinary Time 2026

For I wish that I myself could be accursed and cut off from Christ for the sake of my brethren, my kinsmen by race.

Social scientists are obsessed with kinship, and my own tribe of evolutionary anthropologists more than other social scientists. It is not difficult to see why. On any standard Darwinian account of social behaviour, genetic-relatedness must have an important role to play. Kin selection is the evolutionary selection of self-sacrificial behaviour for the sake of our relatives, concisely captured by J.B.S. Haldane’s quip that he would willingly die for two brothers or eight cousins. 

The textbook example of this is found among eusocial insects like bees and ants, in whose colonies the vast majority of individuals are sterile females, whose lives are dedicated to helping their mother queen reproduce with a handful of fertile males. At first glance, this makes little evolutionary sense, until we realise that—due to a quirk of their reproductive biology call haplodiploidy—worker bees share up to 75% of their genes with their sisters but only 50% with their own offspring: thus, it is more genetically advantageous for them to help to raise sisters than to raise children of their own. 

Now, it turns out that there is very little empirical evidence that this reproductive anomaly actually causally accounts for the evolution of eusociality, but that hasn’t stopped biologists from citing it as an example of how genetic relatedness drives altruism—so strong is the intuitive appeal of the idea. Kin selection has even become the foundation of some of our theories of altruism more generally, especially paired with the idea of fictive kinship.

+++

Fictive kinship is exactly what it sounds like: familial relatedness that is more made than given, more cultural than biological, and so from a certain reductive standpoint, more imagined than real. But no one doubts that the effects of fictive kinship are real. At its most superficial level, it is the source of familial rhetoric in political, ethnic, and religious contexts. Consider: motherland and fraternité, brothers and sisters in Christ, the Reverends Mother and Father—and here, St Paul’s “my brethren, my kinsmen by race”.  

Of course, ethnicity and nationality are not totally independent of genetic relatedness: but the genetic similarities within and differences between ethnic and national groups are much smaller than people often assume. For starters, any two random human beings already share almost all their genetic sequences—after all, as a whole, our species even shares 98.8% of our genes with chimpanzees. But even amongst the genetic sequences subject to individual variation, only about 10% of those are discernible across ethnic or national boundaries; 90% of genetic differences occur between individuals within populations. From a genetic standpoint, race may not be entirely fictional, but it is at least mostly mythical. 

But myths are powerful things, for better or for worse. The idea that we are, regardless of our genetic relatedness, kin—brothers from another mother; sisters from another mister; as they say…—this idea is, and has always been, one of profound theological significance. This morning, we hear of St Paul’s own allegiance to Israel, so heartfelt that he would almost choose damnation in exchange for his people’s salvation; a repudiation of our sordid history of Christian anti-semitism, if ever there was one.

And yet, St Paul’s greatest contribution to the Christian faith is arguably his work as the apostle to the Gentiles, which transforms this minor sect of Second Temple Judaism into the universal and universalising religion to which we now belong. Remarkably, the language of kinship still survives even this transition across ethnic boundaries. Just a few paragraphs earlier, he describes salvation in terms of adoption into God’s family, which enables him to talk about both Jews and Gentiles as “brothers and sisters” in Christ, which he does extensively—it is his favourite manner of addressing fellow Christians.

+++

The fact is that our daily lives do not live up to this loft rhetoric. Priests are addressed in parental terms, but on the whole, we fail to love our people as parents ought to do. The habit, admittedly more common among evangelical  nonconformists,  of referring one another as siblings is more-or-less foreign to Anglicans, except in the safe formality of the prayer book’s “dearly beloved brethren”. And while, for some, the Christian community is their found family, their chosen kin, for most, the Church is a place to come to briefly and then leave again to spend time with our real families.   

But this should not be so, and the challenge before us is to take more seriously the idea that we live in a household of faith, that we belong to one another, and owe one another certain duties. I confess that I do not yet know what this means specifically for us here at St Mary Magdalen’s. And I am eager to know what you might think it might mean for us to call this place a house of God, our home together, where we gather to eat and drink as families do, even to eat and drink this Sacrament of unity and love, which binds us together even as our baptisms do, whose water is thicker and richer than blood. 

I yearn to know what it means, what it looks like for your priests to love you with fatherly and motherly love. I yearn to know what it means, what it looks like for us to love one another as brothers and sisters, ever and indelibly committed to one another, even in the midst of the petty squabbles that is the soundtrack of most homes, even the most functional and loving of families. 

Pray then, let us essay to discern such things together, my dearly beloved.