Galatians 3:22-29; Psalm 104(105):2-7; Luke 11:27-28
It is (fortunately) a little unusual to have a homily interrupted by a shouting member of the congregation - and when it does happen there is usually much tutting and shushing and even expulsion of the individual concerned. A homilist with the skills of an experienced stand up comic might have a library of put downs to deal out to the heckler.
Not Jesus - Jesus's response is exemplary, and teaches us all how to respond to an interruption. He accepts the call, and responds with a word of consolation and truth: happiness (perhaps a better word might be comfort, or peacefulness) is in the heart that hears the word of God and Keeps it.
Jesus is recalling the annunciation - Mary heard the call of God, and not only kept it, she treasured it and nurtured it and in a very real human and female way - she physically grew it within her. Jesus is not admonishing the heckler at all, he is agreeing with her!
Today, following yesterdays Rosary day, is a great day to ponder on Mary's response to God, and to yearn for the grace to move, even slightly, towards her way of responding.