Miriam called her mother with some great news. “Ma, I just met a wonderful man. He’s kindhearted, really smart, great sense of humor, very successful, and he is crazy about me.” Brief silence, and then her mother speaks. “Nice, dear. Is he Jewish?”

While that is in the format of a Jewish joke, the exact same conversation could be heard from a pair of Pakistanis, Catholics, Latinos, Japanese, or Russians. Or anybody else. I knew a woman from Milan, Italy, who complained that all three of her daughters had married stranieri – foreigners. The men referred to were an American, a native of Venice and a man who hailed from a particular suburb of Milan that most Milanese looked down on.

Tribalism is an innate and universal characteristic of humanity. Pre-literate tribes often call themselves by a word that means humans or “the people,” and many refer to other tribes using less complimentary language. Tribalism is of course at the root of racism, nationalism, and a great deal of the wars and miseries in human history.

We don’t know the origin of this sense of belonging to an exclusive group, but we do know that it manifests itself in childhood, and becomes a critical feature of social interactions throughout adolescence. Tribalism expanded at some point beyond the extended family unit to encompass actual tribes and eventually even nations. But at its root it remains what it was inherited by early humans from a long phylogenetic ancestry going back to the dawn of mammals at least. And that is a recognition of familial ties as paramount in the definition of individual worth.

You are a bona fide member of a tribe if your biological parents were members, and that gives one a connection to all the other members, since all can be connected to each other through birth.

This family connection principle is so firmly rooted in our inner instincts that evidence for it is everywhere. The question “who are you” generally means: what is your tribal history, who were your parents, and what tribe were they part of? “Where are you from?” has the same general purpose. When a white person meets someone they have spoken to on the phone and see that they’re Black (even though they didn’t “sound” Black) the first reaction is “Oh, you’re Black” (or Asian or white or whatever you didn’t expect). But racism is only most extreme form of tribalism.

The concept that a person’s membership in a tribe is inherited makes a lot of sense, actually, since early on everyone could see that parental traits were inherited in offspring. The Biblical phrase “each according to its kind” is a very early biological understanding of the principle of inheritance of characteristics, whereby animals only give birth to animals that are just like them. This was also seen in human beings, and it became visibly obvious that tall tribes had tall children, hairy tribes kept having hairy kids, and so on. In modern days this observation has become the well understood science of genetics. In older days the term used was “blood.” When people used to say, “Of course he’s clever – it’s in his blood” referring to the intelligence of his forebears, now they would substitute the word genes for blood.

This is why detailed genealogies, usually oral, but later written down, have been so important everywhere in the world from Pacific islands to the Middle East. As empires spread and nations conquered each other, it became crucial to be identified as a member of the conquering tribe vs. the losers, so one would not be cast as a slave by mistake.

In a small backwater of the Roman Empire, amongst a very difficult tribe with some very odd religious beliefs, a teacher or prophet began preaching a number of strange and entirely subversive ideas. Among these was a certain message of love that seemed to transcend tribal boundaries. Jesus Christ certainly was a member of his own tribe and a follower of their holy books and historical religion. But his claims and his call were different from those of most of the other itinerant preachers who could be found everywhere in those days. He defied the authorities of his own religion, and proclaimed himself the Son of Man, leading many to consider him to be the long-promised king who would change the world for his tribe. But Jesus had other messages as well. He told people that they should love their neighbor, which in those days could mean people belonging to other tribes. He told a story about how a foreigner (the good Samaritan) was just as worthy as the members of his own tribe. He even ministered to a Roman officer. This was something new and simply revolutionary.

After his death, his followers took this new idea further. The Apostle Paul wrote, “In Christ there is neither Greek nor Jew, slave nor free, male nor female.” Probably the most revolutionary and idealist words ever written.

Christianity continued on the path of anti-tribalism for the next millennium, and despite the inborn human drive to define us and them as opposing tribes, has rarely officially strayed from that path. Missionaries have never said “Oh, no, we don’t want to go there. Those people are not really like us, and we see no reason for them to hear the word of Christ.” Just the opposite. From Patrick who landed on the island of terrifying savages called the Irish, to the more modern missionaries who went to Africa, Japan, and many hostile parts of the earth, Christianity has added every nation on the planet to the list of Greeks and Jews, Barbarians and Scythians.

What is the real significance of this revolutionary refusal to consider tribal or national identity when if comes to finding the path to God? It’s a refutation of the importance of blood (or genes, or inheritance or genealogy) when it comes to anything important. What Christ and his Apostles taught the world was that it doesn’t matter if you can trace your lineage back to David or Moses or Abraham. All are equal in Christ. It doesn’t matter if you were born into a family with a proud legacy of good deeds, high education, with devout and well regarded ancestors, or if you were an orphan born out of wedlock to a prostitute and a thief and grew up in poverty and ignorance. Either way you are an equal member of the tribe of man, and therefore a child of God, and you, even you, are worthy of the love of Christ.

This message is still as crazy, controversial and radical as it was 2000 years ago. It goes against all of our inborn instincts, and of course we all know that in practice many Christians have failed to heed it.

But there is no denying that God sent His son into the world to tell us and show us many things, and this is one of them.

And so the question is, if it doesn’t matter whether or not you are the “blood” or genetic or genealogical descendant of Abraham or Caesar or Charlemagne or whoever, does it matter if you are a blood descendant of Adam? This is in a way a trivial question, because of course we are all descendants of everyone who lived 6000 to 10000 years ago, as Joshua Swamidass (in The Genealogical Adam and Eve) and others have clearly demonstrated. But if there were some isolated people who perhaps didn’t get to be part of the blood relations of Adam’s descendants, does it matter? Not to Christianity, it doesn’t. Sin is not a genetic trait. Knowledge of God is not a genetic trait. The Fall affected all men not because as Adam’s descendants we somehow inherited a gene for sin. Original sin along with the image of God has indeed been passed down through the generations, because of who we all are biologically, and because of who we are as God’s creation. Bloodlines do not matter for a Christian. Christ destroyed “us against them” ideology. Christ washed away the idea of blood with his blood and promised salvation to all.