St. Hilary on the Brothers of the Lord

St. Hilary of Poitiers ca. 300-368

[S]ome very depraved men…view that there were many brothers of our Lord as a point of tradition. If there had been sons of Mary who were not rather produced from a previous marriage of Joseph’s, Mary never would have been transferred to the Apostle John as his mother at the time of the Passion, nor would the Lord have said to them both, “Woman, behold your son,” and to John, “Behold your mother,” unless perhaps He was leaving His disciples’ filial love in order to comfort her who was left behind. (Commentary on Matthew, 1.4)