And it was told him by some who said, Your mother and your brothers stand outside, desiring to see you.
Read Chapter 8
George Leo Haydock
AD 1849
These brethren were not the sons of the blessed Virgin Mary, mother of God, as Helvidius wickedly taught; nor yet the sons of Joseph, by another wife; for, as St. Jerome writeth, not only Mary, but Joseph also, observed virginity. (Contra Helvidium, chap. ix. et ibidem, chap. viii.)
In the scriptural idiom, cousins are called brethren. (Bristow)
And how else could they have said that His mother and His brethren were standing without?.
But whenever a dispute arises about the nativity, all who reject it as creating a presumption in favour of the reality of Christ's flesh, wilfully deny that God Himself was born, on the ground that He asked, "Who is my mother, and who are my brethren? "