In the wake of the massacre at the Tree of Life synagogue in Pittsburgh, many people are struggling to understand the roots of Robert Bowers’s hatred.

Bowers, who allegedly shouted “All Jews must die” as he opened fire, has an established record of anti-Semitic rants on social media. There is some debate about whether Bowers’ alleged violence was inspired by statements by the current president or actually provoked by a sense that President Trump had “betrayed” right-wing radicals. Bowers himself, however, squarely grounds his perspective in a different source: the Bible.

On his Gab page, Bowers has written, “jews are the children of satan. (john 8:44)… the lord Jesus Christ is come in the flesh.” On this single point Bowers is not wrong: The Gospel of John does in fact identify “the Jews” (hoi Ioudaioi, in Greek) as being “of [their] father the Devil.” Throughout the Gospel of John, in fact, “the Jews” are repeatedly identified as the opponents of Jesus. Not some group of Jews, not some fringe group, but “the Jews.” While some New Testament scholars might protest that “Ioudaioi” should actually be translated as “people from Judea” and, thus, not taken as a reference to an entire religio-ethnic group at all, that’s simply not how it is translated in English New Testaments.

While the association of Jews with Satan is most explicit in the Gospel of John, in all four of the canonical gospels a (presumably) Jewish crowd calls for the death of Jesus, and Jewish authorities spearhead efforts to arrest and convict him. In Matthew, the Roman governor Pilate asks the people whom they want to see released: Jesus or a common criminal. When they call for the criminal, Pilate washes his hands of responsibility for the death of Jesus. The crowd responds in unison, “His blood be on our hands and on the hands of our children” (Matthew 25:27). The Jews, the writings of the New Testament tell us, shoulder responsibility for the death of Jesus. This is despite the fact that, in first-century Roman Judea, only the Romans had the power to condemn a man to death.

The legacy of these stories is devastatingly clear. They laid the groundwork for and nurtured nearly two thousand years of anti-Semitism. There is no doubt that stories about the death of Jesus can provoke violence. In the medieval period, when the death of Jesus was publicly performed in passion plays at Easter time, riled-up audience members would spill out onto the streets and attack Jewish members of their communities. To be sure, as Paul B. Sturtevant has written in a brilliant piece for The Public Medievalist, the situation was complicated. Some Christians, for example, were paid by Jews to protect them. But the legacy of this period is felt even today in unsympathetic portraits of Jesus’s Jewish contemporaries in TV adaptations of the Easter story.

Historically speaking, the demonization of Jews was a rhetorical strategy for the first followers of Jesus. Annette Yoshiko Reed, a professor in the department of Hebrew and Judaic studies at New York University, told The Daily Beast that this was “just one of a broad continuum of different strategies by which followers of Jesus made sense of their relation to Judaism.” John 8:44 was part of “an inner-Christian debate in which there were also others who were stressing instead the Jewishness of both Jesus and authentic forms of Christianity.

All of that is lost when the Gospels are read in a world in the modern world. “The shooter’s quotation of this passage,” said Reed, “is an example of what happens when that one strategy is taken out of its original context and re-read in terms of distinctly modern notions of identity as predicated on biologically essentialized ideas of ‘race.’”

Mark Leuchter, a professor of religion and Judaism at Temple University agrees. “Once the New Testament became holy specifically to Christians, the original context for [the] debate was lost.” Statements from the New Testament “became [for some] the justification for anti-Jewish violence and hatred… and are still used to facilitate anti-Jewish bigotry in ways that many Christians don’t even realize.” As evidence of this subtle bias Leuchter cited the use of the term “Pharisee” by “well-meaning Christians” as an insult against people obsessed with law, when the historical Pharisees were actually more like ancient liberal activists. Examples like this contribute to what Leuchter calls a “cartoon version of Judaism that is presented as devoid of morality, holiness or humane values.”

Of course, while many American Christians may hold outdated views about Judaism, it is only a tiny fraction of them that resort to outright violence. Meghan Henning, a professor of Christian origins at the University of Dayton, told me that “a segment of Christians in the United States, who have been shaped by the ideals of white nationalism, still use anti-Semitism as a lens for reading their Bibles.”

It is, as Reed says, the transplanting of texts from a period when “whiteness had no meaning” to the modern context of contemporary American white supremacy that gives this passage its horrifying power.