Are You Part of The Family of God?

What is it that makes someone part of the family of God? Many think that knowledge of Jesus makes them a part of the family? Or familiarity with Jesus makes them a part of the family? Observing some rite or tradition makes them part of the family. None of these make one a part of the family. Jesus said, "...For whoever does the will of My Father who is in heaven, he is My brother and sister and mother."