Whoever does the will of God is my brother and sister and mother. Among the many accusations that must have been labeled against Jesus is Jesus' attempt to reconstitute the family. The family was a very essential social unit in Jesus' culture. The family not only gave an individual his/her identity, but it also guaranteed his/her place in the society. A family guaranteed kinship. It was kinship that guaranteed Israel as a nation its continued existence because everything " Israel" was imparted to an individual from the family. As such, one was bound to the family by ties that could never be broken. It must have come as a shock, then, to the mother and brothers of Jesus to hear him utter words that were closest to denouncing his family. Jesus' immediate family was concerned about his safety and wellbeing (recall Jesus has already been labeled insane and out of his mind), and when they came looking for him, he was heard saying that his mother and brothers were those gathered about him.
Jesus certainly appreciated the customs and traditions of his people (he was always in the synagogue on the Sabbath etc.) He must have appreciated his people's understanding of the family. He saw in the tradition of his people some inherent good. But he also wanted this good to be "unlocked" and shared with others. He understood that Israel as a people had been elected by God to be a means of blessing and salvation for others. Part of being a blessing to the nations was opening themselves up and inviting others to share in their life and tradition. Jesus saw in his community’s understanding of the family something that would be instrumental in his ushering in of the Kingdom of God. And he wanted to extend this understanding to the nations.
When Jesus' mother and brothers come looking for him, Jesus utilized the opportunity to invite the crowd to re-think their understanding of the family. Instead of restricting kinship to blood relations, Jesus presents a new understanding of kinship that extends to the entirety of creation. In this sense, whoever lives according to the will of God becomes a member of my family. Mary obviously was a doer of God's word (behold I am the handmaid of the Lord), as were the people gathered about him listening to him. Jesus did not denounce his immediate family. However, he was inviting those who were listening to him to imitate his mother who had listened to God’s word and did as God had commanded. He was inviting those gathered to listen to him to open themselves up and allow the spirit to transform them into members of Jesus' larger family: the kingdom of God.