By Luke Lancaster
Most Protestants think that because the brothers and sisters of the Lord are mentioned in the Gospels that that disproves Mary’s perpetual virginity. However, there was no word for cousin or close relative in Hebrew (the language of the Jews) or Aramaic (the language of the day). Instead, all family members were called either "brother" or "sister" as a part of the culture. This is even the case today for many African cultures, who call every member of their kin a "brother."
With this background knowledge in mind, should we definitively assume that the "brothers" and "sisters" of the Lord are children of Mary and Joseph? I don't think so. For Jesus could have referred to either His cousins or His close relatives, and we would have no way of knowing. Consider the example from Jewish culture in Genesis 14:14, where Abraham called his nephew Lot “brother.” Lot was not a blood brother, but was Abraham's brothers' son. But, according to culture, that made Lot his "brother."
The New Testament follows this Jewish cultural expression as well. For example, in Mark 6:17, King Herod's half-brother Philip was called his "brother." It reads, "For Herod had sent and seized John, and bound him in prison for the sake of Herodias, his brother Philip’s wife; because he had married her." Protestant Scripture scholar Richard Baukham argued in his essay, “The Brothers and Sisters of Jesus: An Epiphanian Response to John Meier” that, if Scripture can call Philip a "brother" instead of a "half-brother," then couldn't Jesus's "brothers" be truly "half-brothers"?
Beyond the New Testament, Dr. Richard Baukham also points out that the extrabiblical writings do not believe that Jesus's brothers and sisters were children of Mary. For in the mid-second century, the three works the Gospel of Peter, the Protoevangelium of James, and The Infancy Gospel of Thomas, “the idea that Jesus’ brothers and sisters were Joseph’s children by a previous marriage is taken entirely for granted,” and “is the only piece of nonbiblical information common to these works.” So, the Old Testament, the New Testament, and the writings immediately after the NT all follow the Jewish cultural usage of "brother" and "sister."
Even the founders of the Protestant Reformation, Martin Luther and John Calvin, knew this cultural custom, and that is why they believed in Mary’s perpetual virginity. Luther said, “I am inclined to agree with those who declare that 'brothers' really mean 'cousins' here, for Holy Writ and the Jews always call cousins brothers" (Sermons on John). Calvin responded to the argument that Jesus had “blood-brothers” by saying, "The word brothers, we have formerly mentioned, is employed, agreeably to the Hebrew idiom, to denote any relatives whatever; and, accordingly, Helvidius displayed excessive ignorance in concluding that Mary must have had many sons, because Christ’s brothers are sometimes mentioned" (Commentary on Matthew, Mark, Luke, Vol 2, Matthew 13.53-58 and Mark 6.1-6).
Truly, there is no reason to believe that Jesus had blood-brothers from Mary simply because Scripture speaks of "brothers" and "sisters" of His. It was a common Hebrew practice to call all kin "brothers" and "sisters." The Old Testament, New Testament, extrabiblical writings, and the founders of Protestantism bear credence to this. The doctrine of Mary's perpetual virginity still stands after all is said and done.