This Gospel passage doesn't seem to really say much, and that is because it is only the first part of the story; the second part comes about ten verses later, in 3:31-35, when these family members  actually arrive and “wish to see Jesus.”  Upon hearing this, Jesus asks who his family really is and declares that it consists of those who do the will of God. 

The passage which interrupts these two parts of the one teaching concerns whether Jesus casts out devils by the power of Beelzebub, the prince of demons, or not; His reply to the scribes contains the statement that if a house is divided against itself it will not be able to stand... 

That applies not only to the spiritual conflict between Jesus and the forces of ungodliness, it applies to families and even to individuals as well.  In the only case that we have real power over, our own, we truly must decide where our heart is, whether we have an undivided loyalty to Christ and His Kingdom or not.  That does not mean that we have achieved perfect control over our lives, only that we have set ourselves to know, love, and serve Christ, His Father, and His Spirit and that we will do our very best to make all our choices in the light of that decision.  Only then can we claim to speak and work in God's name as we try to bring unity to our own families, our communities, and to the world.

This is what our Baptism has called us to and what we have, usually as young adults, ratified and chosen for our selves.  So: where do we stand on this question?  And do we indeed turn first and always to the Holy Three to be our inspiration and our strength?