Updated: Mar 11, 2021
By Luke Lancaster
Most Protestants think that the "brothers and sisters of the Lord" mentioned in the Gospels disprove Mary’s perpetual virginity. However, there was no word for "cousin" or "close relative" in Hebrew or Aramaic (the language of the 1st century). 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." Let's look at how the Old Testament, New Testament, other 2nd century writings, and the Protestant Reformers themselves understood this.
In Genesis 13:8 and 14:14, Abraham called his nephew Lot “brother.” However, Lot was not a blood brother but was Abraham's brother's son (Gen. 14:12). But, according to Jewish culture, all close kin were considered "brother." Some atheists will actually attempt to say that there is a contradiction in Scripture here, for Lot is said to be a nephew and a brother! They simply do not understand that, as Scholar A.R. Fassuet said in his 1998 Bible Dictionary, the Israelites often “distinguished a ‘brother’ as an Israelite by birth, and a ‘neighbor’ a proselyte, and allowed neither title to the Gentiles”.
The New Testament followed this Jewish cultural tradition 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 pointed out that the extrabiblical writings did not believe that Jesus's brothers and sisters were children of Mary. For in the mid-second century, there were three works that gave this idea: The Gospel of Peter, The Protoevangelium of James, and The Infancy Gospel of Thomas. He said of these works, “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 followed 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). Luther knew this Jewish custom, so why do his Protestant successors deny it?
Calvin said that "The word brothers, we have formerly mentioned, is employed, agreeably to the Hebrew idiom, to denote any relatives whatever; and, accordingly, Helvidius [and current Protestants] 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). Calvin also knew of this Jewish custom, yet his successors seem to have forgotten this.
Truly, there is no reason to believe that Jesus had blood-brothers from Mary simply because Scripture spoke 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 all bore credence to this. The doctrine of Mary's perpetual virginity still stands after all is said and done.