Matthew writes of Jesus' own words that compare his
relationship with his followers to his relationship with his mother.
Matthew 12:46-50 (Mark 3:31-35)
While he was still speaking to the crowds, his mother
and his brothers appeared outside, wishing to speak with
him. ... And stretching out his hand toward his disciples,
he said, "Here are my mother and my brothers. For
whoever does the will of my heavenly Father is my
brother, and sister, and mother."