“For whosoever shall do the will of God, the same is my brother, and my sister, and mother.”
Mark 3:35 — Greek Interlinear
Church Fathers on Mark 3:35
Because the relations of the Lord had come to seize upon Him, as if beside Himself, His mother, urged by the sympathy of her love, came to Him.
The brother of the Lord must not be thought to be the sons of the ever-virgin Mary, as Helvidius says [ed. note: The perpetual virginity of the Mother of God is reckoned by White, Bramhall, Patrick and Pearson, amongst the traditions which have ever been held in the Catholic Church. For an account of the heretics who denied it, see Bp. Pearson on the Creed, Art, 3, p. 272, note x., also Catena Aurea in Matt., p 58, note c], nor the sons of Joseph by a former marriage, as some…
But let us be assured that we are His brethren and His sisters, if we do the will of the Father; that we may be joint-heirs with Him, for He discerns us not by sex but by our deeds.